Covid ICYMI

A new study shows that people with long COVID respond differently to COVID vaccines and that the condition may be caused by a dysfunction of the immune system – possibly explaining why some people experience symptoms for months while others recover and resume normal lives. 

The study compared people who already had long COVID with people who had recovered from the virus. Both groups had not yet been vaccinated prior to the study. When researchers analyzed blood samples after people received an initial vaccine dose, they found that people with long COVID and people who had already recovered from the virus had similar immune responses at first. But after 8 weeks, the long-COVID group’s immune response remained elevated, while the other group’s response had declined.

The long-COVID group also showed an extra immune response that tried to fight the virus in a secondary way that researchers didn’t expect. Both groups showed an initial increase in their blood of antibodies that primarily target what’s known as the “spike” protein of the coronavirus, which allows the virus to invade healthy cells. But the long-COVID group also showed a prolonged increased immune response that tried to fight the part of the virus related to how it replicates.

“Theoretically, the production of these antibodies could mean that people are more protected from infection,” said researcher Catherine Le, MD, in a statement. “We also need to investigate if the elevated immune response corresponds with severity or number of long–COVID-19 symptoms.”

Dr. Le is codirector of the COVID-19 Recovery Program at Cedars-Sinai Medical Center in Los Angeles, where the study was conducted.

Study participants agreed in September 2020 to participate in long-term COVID research at Cedars-Sinai. The new analysis was published earlier this year in BMC Infectious Diseases and included 245 people who had long COVID and 86 health care workers who had recovered from COVID but did not have long-term symptoms. 

For the study, long COVID was defined as having symptoms that lasted more than 12 weeks. Common long-COVID symptoms are fatigue, shortness of breath, and brain dysfunction such as confusion and forgetfulness.

The authors said it’s unclear why the two groups had different immune responses and also noted that their study was limited by a small sample size. Their research of blood samples is ongoing, with the goals of identifying a way to diagnose long COVID with a laboratory test and of better understanding what causes the condition.

A version of this article first appeared on WebMD.com.

A new study shows that people with long COVID respond differently to COVID vaccines and that the condition may be caused by a dysfunction of the immune system – possibly explaining why some people experience symptoms for months while others recover and resume normal lives. 

The study compared people who already had long COVID with people who had recovered from the virus. Both groups had not yet been vaccinated prior to the study. When researchers analyzed blood samples after people received an initial vaccine dose, they found that people with long COVID and people who had already recovered from the virus had similar immune responses at first. But after 8 weeks, the long-COVID group’s immune response remained elevated, while the other group’s response had declined.

The long-COVID group also showed an extra immune response that tried to fight the virus in a secondary way that researchers didn’t expect. Both groups showed an initial increase in their blood of antibodies that primarily target what’s known as the “spike” protein of the coronavirus, which allows the virus to invade healthy cells. But the long-COVID group also showed a prolonged increased immune response that tried to fight the part of the virus related to how it replicates.

“Theoretically, the production of these antibodies could mean that people are more protected from infection,” said researcher Catherine Le, MD, in a statement. “We also need to investigate if the elevated immune response corresponds with severity or number of long–COVID-19 symptoms.”

Dr. Le is codirector of the COVID-19 Recovery Program at Cedars-Sinai Medical Center in Los Angeles, where the study was conducted.

Study participants agreed in September 2020 to participate in long-term COVID research at Cedars-Sinai. The new analysis was published earlier this year in BMC Infectious Diseases and included 245 people who had long COVID and 86 health care workers who had recovered from COVID but did not have long-term symptoms. 

For the study, long COVID was defined as having symptoms that lasted more than 12 weeks. Common long-COVID symptoms are fatigue, shortness of breath, and brain dysfunction such as confusion and forgetfulness.

The authors said it’s unclear why the two groups had different immune responses and also noted that their study was limited by a small sample size. Their research of blood samples is ongoing, with the goals of identifying a way to diagnose long COVID with a laboratory test and of better understanding what causes the condition.

A version of this article first appeared on WebMD.com.

A new study shows that people with long COVID respond differently to COVID vaccines and that the condition may be caused by a dysfunction of the immune system – possibly explaining why some people experience symptoms for months while others recover and resume normal lives. 

The study compared people who already had long COVID with people who had recovered from the virus. Both groups had not yet been vaccinated prior to the study. When researchers analyzed blood samples after people received an initial vaccine dose, they found that people with long COVID and people who had already recovered from the virus had similar immune responses at first. But after 8 weeks, the long-COVID group’s immune response remained elevated, while the other group’s response had declined.

The long-COVID group also showed an extra immune response that tried to fight the virus in a secondary way that researchers didn’t expect. Both groups showed an initial increase in their blood of antibodies that primarily target what’s known as the “spike” protein of the coronavirus, which allows the virus to invade healthy cells. But the long-COVID group also showed a prolonged increased immune response that tried to fight the part of the virus related to how it replicates.

“Theoretically, the production of these antibodies could mean that people are more protected from infection,” said researcher Catherine Le, MD, in a statement. “We also need to investigate if the elevated immune response corresponds with severity or number of long–COVID-19 symptoms.”

Dr. Le is codirector of the COVID-19 Recovery Program at Cedars-Sinai Medical Center in Los Angeles, where the study was conducted.

Study participants agreed in September 2020 to participate in long-term COVID research at Cedars-Sinai. The new analysis was published earlier this year in BMC Infectious Diseases and included 245 people who had long COVID and 86 health care workers who had recovered from COVID but did not have long-term symptoms. 

For the study, long COVID was defined as having symptoms that lasted more than 12 weeks. Common long-COVID symptoms are fatigue, shortness of breath, and brain dysfunction such as confusion and forgetfulness.

The authors said it’s unclear why the two groups had different immune responses and also noted that their study was limited by a small sample size. Their research of blood samples is ongoing, with the goals of identifying a way to diagnose long COVID with a laboratory test and of better understanding what causes the condition.

A version of this article first appeared on WebMD.com.

COVID-19 is a potentially severe systemic disease caused by SARS-CoV-2. SARS-CoV and Middle East respiratory syndrome (MERS-CoV) caused fatal epidemics in Asia in 2002 to 2003 and in the Arabian Peninsula in 2012, respectively. In 2019, SARS-CoV-2 was detected in patients with severe, sometimes fatal pneumonia of previously unknown origin; it rapidly spread around the world, and the World Health Organization declared the disease a pandemic on March 11, 2020. SARS-CoV-2 is a β-coronavirus that is genetically related to the bat coronavirus and SARS-CoV; it is a single-stranded RNA virus of which several variants and subvariants exist. The SARS-CoV-2 viral particles bind via their surface spike protein (S protein) to the angiotensin-converting enzyme 2 receptor present on the membrane of several cell types, including epidermal and adnexal keratinocytes.^1,2 The α and δ variants, predominant from 2020 to 2021, mainly affected the lower respiratory tract and caused severe, potentially fatal pneumonia, especially in patients older than 65 years and/or with comorbidities, such as obesity, hypertension, diabetes, and (iatrogenic) immunosuppression. The ο variant, which appeared in late 2021, is more contagious than the initial variants, but it causes a less severe disease preferentially affecting the upper respiratory airways.³ As of April 5, 2023, more than 762,000,000 confirmed cases of COVID-19 have been recorded worldwide, causing more than 6,800,000 deaths.⁴

Early studies from China describing the symptoms of COVID-19 reported a low frequency of skin manifestations (0.2%), probably because they were focused on the most severe disease symptoms.⁵ Subsequently, when COVID-19 spread to the rest of the world, an increasing number of skin manifestations were reported in association with the disease. After the first publication from northern Italy in spring 2020, which was specifically devoted to skin manifestations of COVID-19,⁶ an explosive number of publications reported a large number of skin manifestations, and national registries were established in several countries to record these manifestations, such as the American Academy of Dermatology and the International League of Dermatological Societies registry,^7,8 the COVIDSKIN registry of the French Dermatology Society,⁹ and the Italian registry.¹⁰ Highlighting the unprecedented number of scientific articles published on this new disease, a PubMed search of articles indexed for MEDLINE search using the terms SARS-CoV-2 or COVID-19, on April 6, 2023, revealed 351,596 articles; that is more than 300 articles published every day in this database alone, with a large number of them concerning the skin.

SKIN DISEASSES ASSOCIATED WITH COVID-19

There are several types of COVID-19–related skin manifestations, depending on the circumstances of onset and the evolution of the pandemic.

Skin Manifestations Associated With SARS-CoV-2 Infection

The estimated incidence varies greatly according to the published series of patients, possibly depending on the geographic location. The estimated incidence seems lower in Asian countries, such as China (0.2%)⁵ and Japan (0.56%),¹¹ compared with Europe (up to 20%).⁶ Skin manifestations associated with SARS-CoV-2 infection affect individuals of all ages, slightly more females, and are clinically polymorphous; some of them are associated with the severity of the infection.¹² They may precede, accompany, or appear after the symptoms of COVID-19, most often within a month of the infection, of which they rarely are the only manifestation; however, their precise relationship to SARS-CoV-2 is not always well known. They have been classified according to their clinical presentation into several forms.^13-15

Morbilliform Maculopapular Eruption—Representing 16% to 53% of skin manifestations, morbilliform and maculopapular eruptions usually appear within 15 days of infection; they manifest with more or less confluent erythematous macules that may be hemorrhagic/petechial, and usually are asymptomatic and rarely pruritic. The rash mainly affects the trunk and limbs, sparing the face, palmoplantar regions, and mucous membranes; it appears concomitantly with or a few days after the first symptoms of COVID-19 (eg, fever, respiratory symptoms), regresses within a few days, and does not appear to be associated with disease severity. The distinction from maculopapular drug eruptions may be subtle. Histologically, the rash manifests with a spongiform dermatitis (ie, variable parakeratosis; spongiosis; and a mixed dermal perivascular infiltrate of lymphocytes, eosinophils and histiocytes, depending on the lesion age)(Figure 1). The etiopathogenesis is unknown; it may involve immune complexes to SARS-CoV-2 deposited on skin vessels. Treatment is not mandatory; if necessary, local or systemic corticosteroids may be used.

Vesicular (Pseudovaricella) Rash—This rash accounts for 11% to 18% of all skin manifestations and usually appears within 15 days of COVID-19 onset. It manifests with small monomorphous or varicellalike (pseudopolymorphic) vesicles appearing on the trunk, usually in young patients. The vesicles may be herpetiform, hemorrhagic, or pruritic, and appear before or within 3 days of the onset of mild COVID-19 symptoms; they regress within a few days without scarring. Histologically, the lesions show basal cell vacuolization; multinucleated, dyskeratotic/apoptotic or ballooning/acantholytic epidermal keratinocytes; reticular degeneration of the epidermis; intraepidermal vesicles sometimes resembling herpetic vesicular infections or Grover disease; and mild dermal inflammation. There is no specific treatment.

Urticaria—Urticarial rash, or urticaria, represents 5% to 16% of skin manifestations; usually appears within 15 days of disease onset; and manifests with pruritic, migratory, edematous papules appearing mainly on the trunk and occasionally the face and limbs. The urticarial rash tends to be associated with more severe forms of the disease and regresses within a week, responding to antihistamines. Of note, clinically similar rashes can be caused by drugs. Histologically, the lesions show dermal edema and a mild perivascular lymphocytic infiltrate, sometimes admixed with eosinophils.

Chilblainlike Lesions—Chilblainlike lesions (CBLLs) account for 19% of skin manifestations associated with COVID-19¹³ and present as erythematous-purplish, edematous lesions that can be mildly pruritic or painful, appearing on the toes—COVID toes—and more rarely the fingers (Figure 2). They were seen epidemically during the first pandemic wave (2020 lockdown) in several countries, and clinically are very similar to, if not indistinguishable from, idiopathic chilblains, but are not necessarily associated with cold exposure. They appear in young, generally healthy patients or those with mild COVID-19 symptoms 2 to 4 weeks after symptom onset. They regress spontaneously or under local corticosteroid treatment within a few days or weeks. Histologically, CBLLs are indistinguishable from chilblains of other origins, namely idiopathic (seasonal) ones. They manifest with necrosis of epidermal keratinocytes; dermal edema that may be severe, leading to the development of subepidermal pseudobullae; a rather dense perivascular and perieccrine gland lymphocytic infiltrate; and sometimes with vascular lesions (eg, edema of endothelial cells, microthromboses of dermal capillaries and venules, fibrinoid deposits within the wall of dermal venules)(Figure 3).^16-18 Most patients (>80%) with CBLLs have negative serologic or polymerase chain reaction tests for SARS-CoV-2,¹⁹ which generated a lively debate about the role of SARS-CoV-2 in the genesis of CBLLs. According to some authors, SARS-CoV-2 plays no direct role, and CBLLs would occur in young people who sit or walk barefoot on cold floors at home during confinement.^20-23 Remarkably, CBLLs appeared in patients with no history of chilblains during a season that was not particularly cold, namely in France or in southern California, where their incidence was much higher compared to the same time period of prior years. Some reports have supported a direct role for the virus based on questionable observations of the virus within skin lesions (eg, sweat glands, endothelial cells) by immunohistochemistry, electron microscopy, and/or in situ hybridization.^17,24,25 A more satisfactory hypothesis would involve the role of a strong innate immunity leading to elimination of the virus before the development of specific antibodies via the increased production of type 1 interferon (IFN-1); this would affect the vessels, causing CBLLs. This mechanism would be similar to the one observed in some interferonopathies (eg, Aicardi-Goutières syndrome), also characterized by IFN-1 hypersecretion and chilblains.^26-29 According to this hypothesis, CBLLs should be considered a paraviral rash similar to other skin manifestations associated with COVID-19.³⁰

Acro-ischemia—Acro-ischemia livedoid lesions account for 1% to 6% of skin manifestations and comprise lesions of livedo (either reticulated or racemosa); necrotic acral bullae; and gangrenous necrosis of the extremities, especially the toes. The livedoid lesions most often appear within 15 days of COVID-19 symptom onset, and the purpuric lesions somewhat later (2–4 weeks); they mainly affect adult patients, last about 10 days, and are the hallmark of severe infection, presumably related to microthromboses of the cutaneous capillaries (endothelial dysfunction, prothrombotic state, elevated D-dimers). Histologically, they show capillary thrombosis and dermoepidermal necrosis (Figure 4).

Other Reported Polymorphic or Atypical Rashes—Erythema multiforme–like eruptions may appear before other COVID-19 symptoms and manifest as reddish-purple, nearly symmetric, diffuse, occasionally targetoid bullous or necrotic macules. The eruptions mainly affect adults and most often are seen on the palms, elbows, knees, and sometimes the mucous membranes. The rash regresses in 1 to 3 weeks without scarring and represents a delayed cutaneous hypersensitivity reaction. Histologically, the lesions show vacuolization of basal epidermal keratinocytes, keratinocyte necrosis, dermoepidermal detachment, a variably dense dermal T-lymphocytic infiltrate, and red blood cell extravasation (Figure 5).

Leukocytoclastic vasculitis may be generalized or localized. It manifests clinically by petechial/purpuric maculopapules, especially on the legs, mainly in elderly patients with COVID-19. Histologically, the lesions show necrotizing changes of dermal postcapillary venules, neutrophilic perivascular inflammation, red blood cell extravasation, and occasionally vascular IgA deposits by direct immunofluorescence examination. The course usually is benign.

The incidence of pityriasis rosea and of clinically similar rashes (referred to as “pityriasis rosea–like”) increased 5-fold during the COVID-19 pandemic.^31,32 These dermatoses manifest with erythematous, scaly, circinate plaques, typically with an initial herald lesion followed a few days later by smaller erythematous macules. Histologically, the lesions comprise a spongiform dermatitis with intraepidermal exocytosis of red blood cells and a mild to moderate dermal lymphocytic infiltrate.

Erythrodysesthesia, or hand-foot syndrome, manifests with edematous erythema and palmoplantar desquamation accompanied by a burning sensation or pain. This syndrome is known as an adverse effect of some chemotherapies because of the associated drug toxicity and sweat gland inflammation; it was observed in 40% of 666 COVID-19–positive patients with mild to moderate pneumonitis.³³

“COVID nose” is a rare cutaneous manifestation characterized by nasal pigmentation comprising multiple coalescent frecklelike macules on the tip and wings of the nose and sometimes the malar areas. These lesions predominantly appear in women aged 25 to 65 years and show on average 23 days after onset of COVID-19, which is usually mild. This pigmentation is similar to pigmentary changes after infection with chikungunya; it can be treated with depigmenting products such as azelaic acid and hydroquinone cream with sunscreen use, and it regresses in 2 to 4 months.³⁴

Telogen effluvium (excessive and temporary shedding of normal telogen club hairs of the entire scalp due to the disturbance of the hair cycle) is reportedly frequent in patients (48%) 1 month after COVID-19 infection, but it may appear later (after 12 weeks).³⁵ Alopecia also is frequently reported during long (or postacute) COVID-19 (ie, the symptomatic disease phase past the acute 4 weeks’ stage of the infection) and shows a female predominance³⁶; it likely represents the telogen effluvium seen 90 days after a severe illness. Trichodynia (pruritus, burning, pain, or paresthesia of the scalp) also is reportedly common (developing in more than 58% of patients) and is associated with telogen effluvium in 44% of cases. Several cases of alopecia areata (AA) triggered or aggravated by COVID-19 also have been reported^37,38; they could be explained by the “cytokine storm” triggered by the infection, involving T and B lymphocytes; plasmacytoid dendritic cells; natural killer cells with oversecretion of IL-6, IL-4, tumor necrosis factor α, and IFN type I; and a cytotoxic reaction associated with loss of the immune privilege of hair follicles.

Nail Manifestations

The red half-moon nail sign is an asymptomatic purplish-red band around the distal margin of the lunula that affects some adult patients with COVID-19.³⁹ It appears shortly after onset of symptoms, likely the manifestation of vascular inflammation in the nail bed, and regresses slowly after approximately 1 week.⁴⁰ Beau lines are transverse grooves in the nail plate due to the temporary arrest of the proximal nail matrix growth accompanying systemic illnesses; they appear approximately 2 to 3 weeks after the onset of COVID-19.⁴¹ Furthermore, nail alterations can be caused by drugs used to treat COVID-19, such as longitudinal melanonychia due to treatment with hydroxychloroquine or fluorescence of the lunula or nail plate due to treatment with favipiravir.⁴²

Multisystem Inflammatory Syndrome

Multisystem inflammatory syndrome (MIS) is clinically similar to Kawasaki disease; it typically affects children⁴³ and more rarely adults with COVID-19. It manifests with fever, weakness, and biological inflammation and also frequently with skin lesions (72%), which are polymorphous and include morbilliform rash (27%); urticaria (24%); periorbital edema (24%); nonspecific erythema (21.2%); retiform purpura (18%); targetoid lesions (15%); malar rash (15.2%); and periareolar erythema (6%).⁴⁴ Compared to Kawasaki disease, MIS affects slightly older children (mean age, 8.5 vs 3 years) and more frequently includes cardiac and gastrointestinal manifestations; the mortality rate also is slightly higher (2% vs 0.17%).⁴⁵

Confirmed COVID-19 Infection

At the beginning of the pandemic, skin manifestations were reported in patients who were suspected of having COVID-19 but did not always have biological confirmation of SARS-CoV-2 infection due to the unavailability of diagnostic tests or the physical impossibility of testing. However, subsequent studies have confirmed that most of these dermatoses were indeed associated with COVID-19 infection.^9,46 For example, a study of 655 patients with confirmed COVID-19 infection reported maculopapular (38%), vascular (22%), urticarial (15%), and vesicular (15%) rashes; erythema multiforme or Stevens-Johnson–like syndrome (3%, often related to the use of hydroxychloroquine); generalized pruritus (1%); and MIS (0.5%). The study confirmed that CBLLs were mostly seen in young patients with mild disease, whereas livedo (fixed rash) and retiform purpura occurred in older patients with a guarded prognosis.⁴⁶

Remarkably, most dermatoses associated with SARS-CoV-2 infection were reported during the initial waves of the pandemic, which were due to the α and δ viral variants. These manifestations were reported more rarely when the ο variant was predominant, even though most patients (63%) who developed CBLLs in the first wave also developed them during the second pandemic wave.⁴⁷ This decrease in the incidence of COVID-19–associated dermatoses could be because of the lower pathogenicity of the o variant,³ a lower tropism for the skin, and variations in SARS-CoV-2 antigenicity that would induce a different immunologic response, combined with an increasingly stronger herd immunity compared to the first pandemic waves achieved through vaccination and spontaneous infections in the population. Additional reasons may include different baseline characteristics in patients hospitalized with COVID-19 (regarding comorbidities, disease severity, and received treatments), and the possibility that some of the initially reported COVID-19–associated skin manifestations could have been produced by different etiologic agents.⁴⁸ In the last 2 years, COVID-19–related skin manifestations have been reported mainly as adverse events to COVID-19 vaccination.

CUTANEOUS ADVERSE EFFECTS OF DRUGS USED TO TREAT COVID-19

Prior to the advent of vaccines and specific treatments for SARS-CoV-2, various drugs were used—namely hydroxychloroquine, ivermectin, and tocilizumab—that did not prove efficacious and caused diverse adverse effects, including cutaneous eruptions such as urticaria, maculopapular eruptions, erythema multiforme or Stevens-Johnson syndrome, vasculitis, longitudinal melanonychia, and acute generalized exanthematous pustulosis.^49,50 Nirmatrelvir 150 mg–ritonavir 100 mg, which was authorized for emergency use by the US Food and Drug Administration for the treatment of COVID-19, is a viral protease inhibitor blocking the replication of the virus. Ritonavir can induce pruritus, maculopapular rash, acne, Stevens-Johnson syndrome, and toxic epidermal necrolysis; of note, these effects have been observed following administration of ritonavir for treatment of HIV at higher daily doses and for much longer periods of time compared with treatment of COVID-19 (600–1200 mg vs 200 mg/d, respectively). These cutaneous drug side effects are clinically similar to the manifestations caused either directly or indirectly by SARS-CoV-2 infection; therefore, it may be difficult to differentiate them.

DERMATOSES DUE TO PROTECTIVE DEVICES

Dermatoses due to personal protective equipment such as masks or face shields affected the general population and mostly health care professionals⁵¹; 54.4% of 879 health care professionals in one study reported such events.⁵² These dermatoses mainly include contact dermatitis of the face (nose, forehead, and cheeks) of irritant or allergic nature (eg, from preservatives releasing formaldehyde contained in masks and protective goggles). They manifest with skin dryness; desquamation; maceration; fissures; or erosions or ulcerations of the cheeks, forehead, and nose. Cases of pressure urticaria also have been reported. Irritant dermatitis induced by the frequent use of disinfectants (eg, soaps, hydroalcoholic sanitizing gels) also can affect the hands. Allergic hand dermatitis can be caused by medical gloves.

The term maskne (or mask acne) refers to a variety of mechanical acne due to the prolonged use of surgical masks (>4 hours per day for ≥6 weeks); it includes cases of de novo acne and cases of pre-existing acne aggravated by wearing a mask. Maskne is characterized by acne lesions located on the facial area covered by the mask (Figure 6). It is caused by follicular occlusion; increased sebum secretion; mechanical stress (pressure, friction); and dysbiosis of the microbiome induced by changes in heat, pH, and humidity. Preventive measures include application of noncomedogenic moisturizers or gauze before wearing the mask as well as facial cleansing with appropriate nonalcoholic products. Similar to acne, rosacea often is aggravated by prolonged wearing of surgical masks (mask rosacea).^53,54

DERMATOSES REVEALED OR AGGRAVATED BY COVID-19

Exacerbation of various skin diseases has been reported after infection with SARS-CoV-2.⁵⁵ Psoriasis and acrodermatitis continua of Hallopeau,⁵⁶ which may progress into generalized, pustular, or erythrodermic forms,⁵⁷ have been reported; the role of hydroxychloroquine and oral corticosteroids used for the treatment of COVID-19 has been suspected.⁵⁷ Atopic dermatitis patients—26% to 43%—have experienced worsening of their disease after symptomatic COVID-19 infection.⁵⁸ The incidence of herpesvirus infections, including herpes zoster, increased during the pandemic.⁵⁹ Alopecia areata relapses occurred in 42.5% of 392 patients with preexisting disease within 2 months of COVID-19 onset in one study,⁶⁰ possibly favored by the psychological stress; however, some studies have not confirmed the aggravating role of COVID-19 on alopecia areata.⁶¹ Lupus erythematosus, which may relapse in the form of Rowell syndrome,⁶² and livedoid vasculopathy⁶³ also have been reported following COVID-19 infection.

SKIN MANIFESTATIONS ASSOCIATED WITH COVID-19 VACCINES

In parallel with the rapid spread of COVID-19 vaccination,⁴ an increasing number of skin manifestations has been observed following vaccination; these dermatoses now are more frequently reported than those related to natural SARS-CoV-2 infection.^64-70 Vaccine-induced skin manifestations have a reported incidence of approximately 4% and show a female predominance.⁶⁵ Most of them (79%) have been reported in association with messenger RNA (mRNA)–based vaccines, which have been the most widely used; however, the frequency of side effects would be lower after mRNA vaccines than after inactivated virus-based vaccines. Eighteen percent occurred after the adenoviral vector vaccine, and 3% after the inactivated virus vaccine.⁷⁰ Fifty-nine percent were observed after the first dose. They are clinically polymorphous and generally benign, regressing spontaneously after a few days, and they should not constitute a contraindication to vaccination.Interestingly, many skin manifestations are similar to those associated with natural SARS-CoV-2 infection; however, their frequency and severity does not seem to depend on whether the patients had developed skin reactions during prior SARS-CoV-2 infection. These reactions have been classified into several types:

• Immediate local reactions at the injection site: pain, erythema, or edema represent the vast majority (96%) of reactions to vaccines. They appear within 7 days after vaccination (average, 1 day), slightly more frequently (59%) after the first dose. They concern mostly young patients and are benign, regressing in 2 to 3 days.⁷⁰
 

• Delayed local reactions: characterized by pain or pruritus, erythema, and skin induration mimicking cellulitis (COVID arm) and represent 1.7% of postvaccination reactions. They correspond to a delayed hypersensitivity reaction and appear approximately 7 days after vaccination, most often after the first vaccine dose (75% of cases), which is almost invariably mRNA based.⁷⁰

• Urticarial reactions corresponding to an immediate (type 1) hypersensitivity reaction: constitute 1% of postvaccination reactions, probably due to an allergy to vaccine ingredients. They appear on average 1 day after vaccination, almost always with mRNA vaccines.⁷⁰

• Angioedema: characterized by mucosal or subcutaneous edema and constitutes 0.5% of postvaccination reactions. It is a potentially serious reaction that appears on average 12 hours after vaccination, always with an mRNA-based vaccine.⁷⁰

• Morbilliform rash: represents delayed hypersensitivity reactions (0.1% of postvaccination reactions) that appear mostly after the first dose (72%), on average 3 days after vaccination, always with an mRNA-based vaccine.⁷⁰

• Herpes zoster: usually develops after the first vaccine dose in elderly patients (69% of cases) on average 4 days after vaccination and constitutes 0.1% of postvaccination reactions.⁷¹

• Bullous diseases: mainly bullous pemphigoid (90%) and more rarely pemphigus (5%) or bullous erythema pigmentosum (5%). They appear in elderly patients on average 7 days after vaccination and constitute 0.04% of postvaccination reactions.⁷²

• Chilblainlike lesions: several such cases have been reported so far⁷³; they constitute 0.03% of postvaccination reactions.⁷⁰ Clinically, they are similar to those associated with natural COVID-19; they appear mostly after the first dose (64%), on average 5 days after vaccination with the mRNA or adenovirus vaccine, and show a female predominance. The appearance of these lesions in vaccinated patients, who are a priori not carriers of the virus, strongly suggests that CBLLs are due to the immune reaction against SARS-CoV-2 rather than to a direct effect of this virus on the skin, which also is a likely scenario with regards to other skin manifestations seen during the successive COVID-19 epidemic waves.^73-75

• Reactions to hyaluronic acid–containing cosmetic fillers: erythema, edema, and potentially painful induration at the filler injection sites. They constitute 0.04% of postvaccination skin reactions and appear 24 hours after vaccination with mRNA-based vaccines, equally after the first or second dose.⁷⁶

• Pityriasis rosea–like rash: most occur after the second dose of mRNA-based vaccines (0.023% of postvaccination skin reactions).⁷⁰

• Severe reactions: these include acute generalized exanthematous pustulosis⁷⁷ and Stevens-Johnson syndrome.⁷⁸ One case of each has been reported after the adenoviral vector vaccine 3 days after vaccination.

Other more rarely observed manifestations include reactivation/aggravation or de novo appearance of inflammatory dermatoses such as psoriasis,^79,80 leukocytoclastic vasculitis,^81,82 lymphocytic⁸³ or urticarial⁸⁴ vasculitis, Sweet syndrome,⁸⁵ lupus erythematosus, dermatomyositis,^86,87 alopecia,^37,88 infection with Trichophyton rubrum,⁸⁹ Grover disease,⁹⁰ and lymphomatoid reactions (such as recurrences of cutaneous T-cell lymphomas [CD30⁺], and de novo development of lymphomatoid papulosis).⁹¹

FINAL THOUGHTS

COVID-19 is associated with several skin manifestations, even though the causative role of SARS-CoV-2 has remained elusive. These dermatoses are highly polymorphous, mostly benign, and usually spontaneously regressive, but some of them reflect severe infection. They mostly were described during the first pandemic waves, reported in several national and international registries, which allowed for their morphological classification. Currently, cutaneous adverse effects of vaccines are the most frequently reported dermatoses associated with SARS-CoV-2, and it is likely that they will continue to be observed while COVID-19 vaccination lasts. Hopefully the end of the COVID-19 pandemic is near. In January 2023, the International Health Regulations Emergency Committee of the World Health Organization acknowledged that the COVID-19 pandemic may be approaching an inflexion point, and even though the event continues to constitute a public health emergency of international concern, the higher levels of population immunity achieved globally through infection and/or vaccination may limit the impact of SARS-CoV-2 on morbidity and mortality. However, there is little doubt that this virus will remain a permanently established pathogen in humans and animals for the foreseeable future.⁹² Therefore, physicians—especially dermatologists—should be aware of the various skin manifestations associated with COVID-19 so they can more efficiently manage their patients.

COVID-19 is a potentially severe systemic disease caused by SARS-CoV-2. SARS-CoV and Middle East respiratory syndrome (MERS-CoV) caused fatal epidemics in Asia in 2002 to 2003 and in the Arabian Peninsula in 2012, respectively. In 2019, SARS-CoV-2 was detected in patients with severe, sometimes fatal pneumonia of previously unknown origin; it rapidly spread around the world, and the World Health Organization declared the disease a pandemic on March 11, 2020. SARS-CoV-2 is a β-coronavirus that is genetically related to the bat coronavirus and SARS-CoV; it is a single-stranded RNA virus of which several variants and subvariants exist. The SARS-CoV-2 viral particles bind via their surface spike protein (S protein) to the angiotensin-converting enzyme 2 receptor present on the membrane of several cell types, including epidermal and adnexal keratinocytes.^1,2 The α and δ variants, predominant from 2020 to 2021, mainly affected the lower respiratory tract and caused severe, potentially fatal pneumonia, especially in patients older than 65 years and/or with comorbidities, such as obesity, hypertension, diabetes, and (iatrogenic) immunosuppression. The ο variant, which appeared in late 2021, is more contagious than the initial variants, but it causes a less severe disease preferentially affecting the upper respiratory airways.³ As of April 5, 2023, more than 762,000,000 confirmed cases of COVID-19 have been recorded worldwide, causing more than 6,800,000 deaths.⁴

Early studies from China describing the symptoms of COVID-19 reported a low frequency of skin manifestations (0.2%), probably because they were focused on the most severe disease symptoms.⁵ Subsequently, when COVID-19 spread to the rest of the world, an increasing number of skin manifestations were reported in association with the disease. After the first publication from northern Italy in spring 2020, which was specifically devoted to skin manifestations of COVID-19,⁶ an explosive number of publications reported a large number of skin manifestations, and national registries were established in several countries to record these manifestations, such as the American Academy of Dermatology and the International League of Dermatological Societies registry,^7,8 the COVIDSKIN registry of the French Dermatology Society,⁹ and the Italian registry.¹⁰ Highlighting the unprecedented number of scientific articles published on this new disease, a PubMed search of articles indexed for MEDLINE search using the terms SARS-CoV-2 or COVID-19, on April 6, 2023, revealed 351,596 articles; that is more than 300 articles published every day in this database alone, with a large number of them concerning the skin.

SKIN DISEASSES ASSOCIATED WITH COVID-19

There are several types of COVID-19–related skin manifestations, depending on the circumstances of onset and the evolution of the pandemic.

Skin Manifestations Associated With SARS-CoV-2 Infection

The estimated incidence varies greatly according to the published series of patients, possibly depending on the geographic location. The estimated incidence seems lower in Asian countries, such as China (0.2%)⁵ and Japan (0.56%),¹¹ compared with Europe (up to 20%).⁶ Skin manifestations associated with SARS-CoV-2 infection affect individuals of all ages, slightly more females, and are clinically polymorphous; some of them are associated with the severity of the infection.¹² They may precede, accompany, or appear after the symptoms of COVID-19, most often within a month of the infection, of which they rarely are the only manifestation; however, their precise relationship to SARS-CoV-2 is not always well known. They have been classified according to their clinical presentation into several forms.^13-15

Morbilliform Maculopapular Eruption—Representing 16% to 53% of skin manifestations, morbilliform and maculopapular eruptions usually appear within 15 days of infection; they manifest with more or less confluent erythematous macules that may be hemorrhagic/petechial, and usually are asymptomatic and rarely pruritic. The rash mainly affects the trunk and limbs, sparing the face, palmoplantar regions, and mucous membranes; it appears concomitantly with or a few days after the first symptoms of COVID-19 (eg, fever, respiratory symptoms), regresses within a few days, and does not appear to be associated with disease severity. The distinction from maculopapular drug eruptions may be subtle. Histologically, the rash manifests with a spongiform dermatitis (ie, variable parakeratosis; spongiosis; and a mixed dermal perivascular infiltrate of lymphocytes, eosinophils and histiocytes, depending on the lesion age)(Figure 1). The etiopathogenesis is unknown; it may involve immune complexes to SARS-CoV-2 deposited on skin vessels. Treatment is not mandatory; if necessary, local or systemic corticosteroids may be used.

Vesicular (Pseudovaricella) Rash—This rash accounts for 11% to 18% of all skin manifestations and usually appears within 15 days of COVID-19 onset. It manifests with small monomorphous or varicellalike (pseudopolymorphic) vesicles appearing on the trunk, usually in young patients. The vesicles may be herpetiform, hemorrhagic, or pruritic, and appear before or within 3 days of the onset of mild COVID-19 symptoms; they regress within a few days without scarring. Histologically, the lesions show basal cell vacuolization; multinucleated, dyskeratotic/apoptotic or ballooning/acantholytic epidermal keratinocytes; reticular degeneration of the epidermis; intraepidermal vesicles sometimes resembling herpetic vesicular infections or Grover disease; and mild dermal inflammation. There is no specific treatment.

Urticaria—Urticarial rash, or urticaria, represents 5% to 16% of skin manifestations; usually appears within 15 days of disease onset; and manifests with pruritic, migratory, edematous papules appearing mainly on the trunk and occasionally the face and limbs. The urticarial rash tends to be associated with more severe forms of the disease and regresses within a week, responding to antihistamines. Of note, clinically similar rashes can be caused by drugs. Histologically, the lesions show dermal edema and a mild perivascular lymphocytic infiltrate, sometimes admixed with eosinophils.

Chilblainlike Lesions—Chilblainlike lesions (CBLLs) account for 19% of skin manifestations associated with COVID-19¹³ and present as erythematous-purplish, edematous lesions that can be mildly pruritic or painful, appearing on the toes—COVID toes—and more rarely the fingers (Figure 2). They were seen epidemically during the first pandemic wave (2020 lockdown) in several countries, and clinically are very similar to, if not indistinguishable from, idiopathic chilblains, but are not necessarily associated with cold exposure. They appear in young, generally healthy patients or those with mild COVID-19 symptoms 2 to 4 weeks after symptom onset. They regress spontaneously or under local corticosteroid treatment within a few days or weeks. Histologically, CBLLs are indistinguishable from chilblains of other origins, namely idiopathic (seasonal) ones. They manifest with necrosis of epidermal keratinocytes; dermal edema that may be severe, leading to the development of subepidermal pseudobullae; a rather dense perivascular and perieccrine gland lymphocytic infiltrate; and sometimes with vascular lesions (eg, edema of endothelial cells, microthromboses of dermal capillaries and venules, fibrinoid deposits within the wall of dermal venules)(Figure 3).^16-18 Most patients (>80%) with CBLLs have negative serologic or polymerase chain reaction tests for SARS-CoV-2,¹⁹ which generated a lively debate about the role of SARS-CoV-2 in the genesis of CBLLs. According to some authors, SARS-CoV-2 plays no direct role, and CBLLs would occur in young people who sit or walk barefoot on cold floors at home during confinement.^20-23 Remarkably, CBLLs appeared in patients with no history of chilblains during a season that was not particularly cold, namely in France or in southern California, where their incidence was much higher compared to the same time period of prior years. Some reports have supported a direct role for the virus based on questionable observations of the virus within skin lesions (eg, sweat glands, endothelial cells) by immunohistochemistry, electron microscopy, and/or in situ hybridization.^17,24,25 A more satisfactory hypothesis would involve the role of a strong innate immunity leading to elimination of the virus before the development of specific antibodies via the increased production of type 1 interferon (IFN-1); this would affect the vessels, causing CBLLs. This mechanism would be similar to the one observed in some interferonopathies (eg, Aicardi-Goutières syndrome), also characterized by IFN-1 hypersecretion and chilblains.^26-29 According to this hypothesis, CBLLs should be considered a paraviral rash similar to other skin manifestations associated with COVID-19.³⁰

Acro-ischemia—Acro-ischemia livedoid lesions account for 1% to 6% of skin manifestations and comprise lesions of livedo (either reticulated or racemosa); necrotic acral bullae; and gangrenous necrosis of the extremities, especially the toes. The livedoid lesions most often appear within 15 days of COVID-19 symptom onset, and the purpuric lesions somewhat later (2–4 weeks); they mainly affect adult patients, last about 10 days, and are the hallmark of severe infection, presumably related to microthromboses of the cutaneous capillaries (endothelial dysfunction, prothrombotic state, elevated D-dimers). Histologically, they show capillary thrombosis and dermoepidermal necrosis (Figure 4).

Other Reported Polymorphic or Atypical Rashes—Erythema multiforme–like eruptions may appear before other COVID-19 symptoms and manifest as reddish-purple, nearly symmetric, diffuse, occasionally targetoid bullous or necrotic macules. The eruptions mainly affect adults and most often are seen on the palms, elbows, knees, and sometimes the mucous membranes. The rash regresses in 1 to 3 weeks without scarring and represents a delayed cutaneous hypersensitivity reaction. Histologically, the lesions show vacuolization of basal epidermal keratinocytes, keratinocyte necrosis, dermoepidermal detachment, a variably dense dermal T-lymphocytic infiltrate, and red blood cell extravasation (Figure 5).

Leukocytoclastic vasculitis may be generalized or localized. It manifests clinically by petechial/purpuric maculopapules, especially on the legs, mainly in elderly patients with COVID-19. Histologically, the lesions show necrotizing changes of dermal postcapillary venules, neutrophilic perivascular inflammation, red blood cell extravasation, and occasionally vascular IgA deposits by direct immunofluorescence examination. The course usually is benign.

The incidence of pityriasis rosea and of clinically similar rashes (referred to as “pityriasis rosea–like”) increased 5-fold during the COVID-19 pandemic.^31,32 These dermatoses manifest with erythematous, scaly, circinate plaques, typically with an initial herald lesion followed a few days later by smaller erythematous macules. Histologically, the lesions comprise a spongiform dermatitis with intraepidermal exocytosis of red blood cells and a mild to moderate dermal lymphocytic infiltrate.

Erythrodysesthesia, or hand-foot syndrome, manifests with edematous erythema and palmoplantar desquamation accompanied by a burning sensation or pain. This syndrome is known as an adverse effect of some chemotherapies because of the associated drug toxicity and sweat gland inflammation; it was observed in 40% of 666 COVID-19–positive patients with mild to moderate pneumonitis.³³

“COVID nose” is a rare cutaneous manifestation characterized by nasal pigmentation comprising multiple coalescent frecklelike macules on the tip and wings of the nose and sometimes the malar areas. These lesions predominantly appear in women aged 25 to 65 years and show on average 23 days after onset of COVID-19, which is usually mild. This pigmentation is similar to pigmentary changes after infection with chikungunya; it can be treated with depigmenting products such as azelaic acid and hydroquinone cream with sunscreen use, and it regresses in 2 to 4 months.³⁴

Telogen effluvium (excessive and temporary shedding of normal telogen club hairs of the entire scalp due to the disturbance of the hair cycle) is reportedly frequent in patients (48%) 1 month after COVID-19 infection, but it may appear later (after 12 weeks).³⁵ Alopecia also is frequently reported during long (or postacute) COVID-19 (ie, the symptomatic disease phase past the acute 4 weeks’ stage of the infection) and shows a female predominance³⁶; it likely represents the telogen effluvium seen 90 days after a severe illness. Trichodynia (pruritus, burning, pain, or paresthesia of the scalp) also is reportedly common (developing in more than 58% of patients) and is associated with telogen effluvium in 44% of cases. Several cases of alopecia areata (AA) triggered or aggravated by COVID-19 also have been reported^37,38; they could be explained by the “cytokine storm” triggered by the infection, involving T and B lymphocytes; plasmacytoid dendritic cells; natural killer cells with oversecretion of IL-6, IL-4, tumor necrosis factor α, and IFN type I; and a cytotoxic reaction associated with loss of the immune privilege of hair follicles.

Nail Manifestations

The red half-moon nail sign is an asymptomatic purplish-red band around the distal margin of the lunula that affects some adult patients with COVID-19.³⁹ It appears shortly after onset of symptoms, likely the manifestation of vascular inflammation in the nail bed, and regresses slowly after approximately 1 week.⁴⁰ Beau lines are transverse grooves in the nail plate due to the temporary arrest of the proximal nail matrix growth accompanying systemic illnesses; they appear approximately 2 to 3 weeks after the onset of COVID-19.⁴¹ Furthermore, nail alterations can be caused by drugs used to treat COVID-19, such as longitudinal melanonychia due to treatment with hydroxychloroquine or fluorescence of the lunula or nail plate due to treatment with favipiravir.⁴²

Multisystem Inflammatory Syndrome

Multisystem inflammatory syndrome (MIS) is clinically similar to Kawasaki disease; it typically affects children⁴³ and more rarely adults with COVID-19. It manifests with fever, weakness, and biological inflammation and also frequently with skin lesions (72%), which are polymorphous and include morbilliform rash (27%); urticaria (24%); periorbital edema (24%); nonspecific erythema (21.2%); retiform purpura (18%); targetoid lesions (15%); malar rash (15.2%); and periareolar erythema (6%).⁴⁴ Compared to Kawasaki disease, MIS affects slightly older children (mean age, 8.5 vs 3 years) and more frequently includes cardiac and gastrointestinal manifestations; the mortality rate also is slightly higher (2% vs 0.17%).⁴⁵

Confirmed COVID-19 Infection

At the beginning of the pandemic, skin manifestations were reported in patients who were suspected of having COVID-19 but did not always have biological confirmation of SARS-CoV-2 infection due to the unavailability of diagnostic tests or the physical impossibility of testing. However, subsequent studies have confirmed that most of these dermatoses were indeed associated with COVID-19 infection.^9,46 For example, a study of 655 patients with confirmed COVID-19 infection reported maculopapular (38%), vascular (22%), urticarial (15%), and vesicular (15%) rashes; erythema multiforme or Stevens-Johnson–like syndrome (3%, often related to the use of hydroxychloroquine); generalized pruritus (1%); and MIS (0.5%). The study confirmed that CBLLs were mostly seen in young patients with mild disease, whereas livedo (fixed rash) and retiform purpura occurred in older patients with a guarded prognosis.⁴⁶

Remarkably, most dermatoses associated with SARS-CoV-2 infection were reported during the initial waves of the pandemic, which were due to the α and δ viral variants. These manifestations were reported more rarely when the ο variant was predominant, even though most patients (63%) who developed CBLLs in the first wave also developed them during the second pandemic wave.⁴⁷ This decrease in the incidence of COVID-19–associated dermatoses could be because of the lower pathogenicity of the o variant,³ a lower tropism for the skin, and variations in SARS-CoV-2 antigenicity that would induce a different immunologic response, combined with an increasingly stronger herd immunity compared to the first pandemic waves achieved through vaccination and spontaneous infections in the population. Additional reasons may include different baseline characteristics in patients hospitalized with COVID-19 (regarding comorbidities, disease severity, and received treatments), and the possibility that some of the initially reported COVID-19–associated skin manifestations could have been produced by different etiologic agents.⁴⁸ In the last 2 years, COVID-19–related skin manifestations have been reported mainly as adverse events to COVID-19 vaccination.

CUTANEOUS ADVERSE EFFECTS OF DRUGS USED TO TREAT COVID-19

Prior to the advent of vaccines and specific treatments for SARS-CoV-2, various drugs were used—namely hydroxychloroquine, ivermectin, and tocilizumab—that did not prove efficacious and caused diverse adverse effects, including cutaneous eruptions such as urticaria, maculopapular eruptions, erythema multiforme or Stevens-Johnson syndrome, vasculitis, longitudinal melanonychia, and acute generalized exanthematous pustulosis.^49,50 Nirmatrelvir 150 mg–ritonavir 100 mg, which was authorized for emergency use by the US Food and Drug Administration for the treatment of COVID-19, is a viral protease inhibitor blocking the replication of the virus. Ritonavir can induce pruritus, maculopapular rash, acne, Stevens-Johnson syndrome, and toxic epidermal necrolysis; of note, these effects have been observed following administration of ritonavir for treatment of HIV at higher daily doses and for much longer periods of time compared with treatment of COVID-19 (600–1200 mg vs 200 mg/d, respectively). These cutaneous drug side effects are clinically similar to the manifestations caused either directly or indirectly by SARS-CoV-2 infection; therefore, it may be difficult to differentiate them.

DERMATOSES DUE TO PROTECTIVE DEVICES

Dermatoses due to personal protective equipment such as masks or face shields affected the general population and mostly health care professionals⁵¹; 54.4% of 879 health care professionals in one study reported such events.⁵² These dermatoses mainly include contact dermatitis of the face (nose, forehead, and cheeks) of irritant or allergic nature (eg, from preservatives releasing formaldehyde contained in masks and protective goggles). They manifest with skin dryness; desquamation; maceration; fissures; or erosions or ulcerations of the cheeks, forehead, and nose. Cases of pressure urticaria also have been reported. Irritant dermatitis induced by the frequent use of disinfectants (eg, soaps, hydroalcoholic sanitizing gels) also can affect the hands. Allergic hand dermatitis can be caused by medical gloves.

The term maskne (or mask acne) refers to a variety of mechanical acne due to the prolonged use of surgical masks (>4 hours per day for ≥6 weeks); it includes cases of de novo acne and cases of pre-existing acne aggravated by wearing a mask. Maskne is characterized by acne lesions located on the facial area covered by the mask (Figure 6). It is caused by follicular occlusion; increased sebum secretion; mechanical stress (pressure, friction); and dysbiosis of the microbiome induced by changes in heat, pH, and humidity. Preventive measures include application of noncomedogenic moisturizers or gauze before wearing the mask as well as facial cleansing with appropriate nonalcoholic products. Similar to acne, rosacea often is aggravated by prolonged wearing of surgical masks (mask rosacea).^53,54

DERMATOSES REVEALED OR AGGRAVATED BY COVID-19

Exacerbation of various skin diseases has been reported after infection with SARS-CoV-2.⁵⁵ Psoriasis and acrodermatitis continua of Hallopeau,⁵⁶ which may progress into generalized, pustular, or erythrodermic forms,⁵⁷ have been reported; the role of hydroxychloroquine and oral corticosteroids used for the treatment of COVID-19 has been suspected.⁵⁷ Atopic dermatitis patients—26% to 43%—have experienced worsening of their disease after symptomatic COVID-19 infection.⁵⁸ The incidence of herpesvirus infections, including herpes zoster, increased during the pandemic.⁵⁹ Alopecia areata relapses occurred in 42.5% of 392 patients with preexisting disease within 2 months of COVID-19 onset in one study,⁶⁰ possibly favored by the psychological stress; however, some studies have not confirmed the aggravating role of COVID-19 on alopecia areata.⁶¹ Lupus erythematosus, which may relapse in the form of Rowell syndrome,⁶² and livedoid vasculopathy⁶³ also have been reported following COVID-19 infection.

SKIN MANIFESTATIONS ASSOCIATED WITH COVID-19 VACCINES

In parallel with the rapid spread of COVID-19 vaccination,⁴ an increasing number of skin manifestations has been observed following vaccination; these dermatoses now are more frequently reported than those related to natural SARS-CoV-2 infection.^64-70 Vaccine-induced skin manifestations have a reported incidence of approximately 4% and show a female predominance.⁶⁵ Most of them (79%) have been reported in association with messenger RNA (mRNA)–based vaccines, which have been the most widely used; however, the frequency of side effects would be lower after mRNA vaccines than after inactivated virus-based vaccines. Eighteen percent occurred after the adenoviral vector vaccine, and 3% after the inactivated virus vaccine.⁷⁰ Fifty-nine percent were observed after the first dose. They are clinically polymorphous and generally benign, regressing spontaneously after a few days, and they should not constitute a contraindication to vaccination.Interestingly, many skin manifestations are similar to those associated with natural SARS-CoV-2 infection; however, their frequency and severity does not seem to depend on whether the patients had developed skin reactions during prior SARS-CoV-2 infection. These reactions have been classified into several types:

• Immediate local reactions at the injection site: pain, erythema, or edema represent the vast majority (96%) of reactions to vaccines. They appear within 7 days after vaccination (average, 1 day), slightly more frequently (59%) after the first dose. They concern mostly young patients and are benign, regressing in 2 to 3 days.⁷⁰
 

• Delayed local reactions: characterized by pain or pruritus, erythema, and skin induration mimicking cellulitis (COVID arm) and represent 1.7% of postvaccination reactions. They correspond to a delayed hypersensitivity reaction and appear approximately 7 days after vaccination, most often after the first vaccine dose (75% of cases), which is almost invariably mRNA based.⁷⁰

• Urticarial reactions corresponding to an immediate (type 1) hypersensitivity reaction: constitute 1% of postvaccination reactions, probably due to an allergy to vaccine ingredients. They appear on average 1 day after vaccination, almost always with mRNA vaccines.⁷⁰

• Angioedema: characterized by mucosal or subcutaneous edema and constitutes 0.5% of postvaccination reactions. It is a potentially serious reaction that appears on average 12 hours after vaccination, always with an mRNA-based vaccine.⁷⁰

• Morbilliform rash: represents delayed hypersensitivity reactions (0.1% of postvaccination reactions) that appear mostly after the first dose (72%), on average 3 days after vaccination, always with an mRNA-based vaccine.⁷⁰

• Herpes zoster: usually develops after the first vaccine dose in elderly patients (69% of cases) on average 4 days after vaccination and constitutes 0.1% of postvaccination reactions.⁷¹

• Bullous diseases: mainly bullous pemphigoid (90%) and more rarely pemphigus (5%) or bullous erythema pigmentosum (5%). They appear in elderly patients on average 7 days after vaccination and constitute 0.04% of postvaccination reactions.⁷²

• Chilblainlike lesions: several such cases have been reported so far⁷³; they constitute 0.03% of postvaccination reactions.⁷⁰ Clinically, they are similar to those associated with natural COVID-19; they appear mostly after the first dose (64%), on average 5 days after vaccination with the mRNA or adenovirus vaccine, and show a female predominance. The appearance of these lesions in vaccinated patients, who are a priori not carriers of the virus, strongly suggests that CBLLs are due to the immune reaction against SARS-CoV-2 rather than to a direct effect of this virus on the skin, which also is a likely scenario with regards to other skin manifestations seen during the successive COVID-19 epidemic waves.^73-75

• Reactions to hyaluronic acid–containing cosmetic fillers: erythema, edema, and potentially painful induration at the filler injection sites. They constitute 0.04% of postvaccination skin reactions and appear 24 hours after vaccination with mRNA-based vaccines, equally after the first or second dose.⁷⁶

• Pityriasis rosea–like rash: most occur after the second dose of mRNA-based vaccines (0.023% of postvaccination skin reactions).⁷⁰

• Severe reactions: these include acute generalized exanthematous pustulosis⁷⁷ and Stevens-Johnson syndrome.⁷⁸ One case of each has been reported after the adenoviral vector vaccine 3 days after vaccination.

Other more rarely observed manifestations include reactivation/aggravation or de novo appearance of inflammatory dermatoses such as psoriasis,^79,80 leukocytoclastic vasculitis,^81,82 lymphocytic⁸³ or urticarial⁸⁴ vasculitis, Sweet syndrome,⁸⁵ lupus erythematosus, dermatomyositis,^86,87 alopecia,^37,88 infection with Trichophyton rubrum,⁸⁹ Grover disease,⁹⁰ and lymphomatoid reactions (such as recurrences of cutaneous T-cell lymphomas [CD30⁺], and de novo development of lymphomatoid papulosis).⁹¹

FINAL THOUGHTS

COVID-19 is associated with several skin manifestations, even though the causative role of SARS-CoV-2 has remained elusive. These dermatoses are highly polymorphous, mostly benign, and usually spontaneously regressive, but some of them reflect severe infection. They mostly were described during the first pandemic waves, reported in several national and international registries, which allowed for their morphological classification. Currently, cutaneous adverse effects of vaccines are the most frequently reported dermatoses associated with SARS-CoV-2, and it is likely that they will continue to be observed while COVID-19 vaccination lasts. Hopefully the end of the COVID-19 pandemic is near. In January 2023, the International Health Regulations Emergency Committee of the World Health Organization acknowledged that the COVID-19 pandemic may be approaching an inflexion point, and even though the event continues to constitute a public health emergency of international concern, the higher levels of population immunity achieved globally through infection and/or vaccination may limit the impact of SARS-CoV-2 on morbidity and mortality. However, there is little doubt that this virus will remain a permanently established pathogen in humans and animals for the foreseeable future.⁹² Therefore, physicians—especially dermatologists—should be aware of the various skin manifestations associated with COVID-19 so they can more efficiently manage their patients.

COVID-19 is a potentially severe systemic disease caused by SARS-CoV-2. SARS-CoV and Middle East respiratory syndrome (MERS-CoV) caused fatal epidemics in Asia in 2002 to 2003 and in the Arabian Peninsula in 2012, respectively. In 2019, SARS-CoV-2 was detected in patients with severe, sometimes fatal pneumonia of previously unknown origin; it rapidly spread around the world, and the World Health Organization declared the disease a pandemic on March 11, 2020. SARS-CoV-2 is a β-coronavirus that is genetically related to the bat coronavirus and SARS-CoV; it is a single-stranded RNA virus of which several variants and subvariants exist. The SARS-CoV-2 viral particles bind via their surface spike protein (S protein) to the angiotensin-converting enzyme 2 receptor present on the membrane of several cell types, including epidermal and adnexal keratinocytes.^1,2 The α and δ variants, predominant from 2020 to 2021, mainly affected the lower respiratory tract and caused severe, potentially fatal pneumonia, especially in patients older than 65 years and/or with comorbidities, such as obesity, hypertension, diabetes, and (iatrogenic) immunosuppression. The ο variant, which appeared in late 2021, is more contagious than the initial variants, but it causes a less severe disease preferentially affecting the upper respiratory airways.³ As of April 5, 2023, more than 762,000,000 confirmed cases of COVID-19 have been recorded worldwide, causing more than 6,800,000 deaths.⁴

Early studies from China describing the symptoms of COVID-19 reported a low frequency of skin manifestations (0.2%), probably because they were focused on the most severe disease symptoms.⁵ Subsequently, when COVID-19 spread to the rest of the world, an increasing number of skin manifestations were reported in association with the disease. After the first publication from northern Italy in spring 2020, which was specifically devoted to skin manifestations of COVID-19,⁶ an explosive number of publications reported a large number of skin manifestations, and national registries were established in several countries to record these manifestations, such as the American Academy of Dermatology and the International League of Dermatological Societies registry,^7,8 the COVIDSKIN registry of the French Dermatology Society,⁹ and the Italian registry.¹⁰ Highlighting the unprecedented number of scientific articles published on this new disease, a PubMed search of articles indexed for MEDLINE search using the terms SARS-CoV-2 or COVID-19, on April 6, 2023, revealed 351,596 articles; that is more than 300 articles published every day in this database alone, with a large number of them concerning the skin.

SKIN DISEASSES ASSOCIATED WITH COVID-19

There are several types of COVID-19–related skin manifestations, depending on the circumstances of onset and the evolution of the pandemic.

Skin Manifestations Associated With SARS-CoV-2 Infection

The estimated incidence varies greatly according to the published series of patients, possibly depending on the geographic location. The estimated incidence seems lower in Asian countries, such as China (0.2%)⁵ and Japan (0.56%),¹¹ compared with Europe (up to 20%).⁶ Skin manifestations associated with SARS-CoV-2 infection affect individuals of all ages, slightly more females, and are clinically polymorphous; some of them are associated with the severity of the infection.¹² They may precede, accompany, or appear after the symptoms of COVID-19, most often within a month of the infection, of which they rarely are the only manifestation; however, their precise relationship to SARS-CoV-2 is not always well known. They have been classified according to their clinical presentation into several forms.^13-15

Morbilliform Maculopapular Eruption—Representing 16% to 53% of skin manifestations, morbilliform and maculopapular eruptions usually appear within 15 days of infection; they manifest with more or less confluent erythematous macules that may be hemorrhagic/petechial, and usually are asymptomatic and rarely pruritic. The rash mainly affects the trunk and limbs, sparing the face, palmoplantar regions, and mucous membranes; it appears concomitantly with or a few days after the first symptoms of COVID-19 (eg, fever, respiratory symptoms), regresses within a few days, and does not appear to be associated with disease severity. The distinction from maculopapular drug eruptions may be subtle. Histologically, the rash manifests with a spongiform dermatitis (ie, variable parakeratosis; spongiosis; and a mixed dermal perivascular infiltrate of lymphocytes, eosinophils and histiocytes, depending on the lesion age)(Figure 1). The etiopathogenesis is unknown; it may involve immune complexes to SARS-CoV-2 deposited on skin vessels. Treatment is not mandatory; if necessary, local or systemic corticosteroids may be used.

Vesicular (Pseudovaricella) Rash—This rash accounts for 11% to 18% of all skin manifestations and usually appears within 15 days of COVID-19 onset. It manifests with small monomorphous or varicellalike (pseudopolymorphic) vesicles appearing on the trunk, usually in young patients. The vesicles may be herpetiform, hemorrhagic, or pruritic, and appear before or within 3 days of the onset of mild COVID-19 symptoms; they regress within a few days without scarring. Histologically, the lesions show basal cell vacuolization; multinucleated, dyskeratotic/apoptotic or ballooning/acantholytic epidermal keratinocytes; reticular degeneration of the epidermis; intraepidermal vesicles sometimes resembling herpetic vesicular infections or Grover disease; and mild dermal inflammation. There is no specific treatment.

Urticaria—Urticarial rash, or urticaria, represents 5% to 16% of skin manifestations; usually appears within 15 days of disease onset; and manifests with pruritic, migratory, edematous papules appearing mainly on the trunk and occasionally the face and limbs. The urticarial rash tends to be associated with more severe forms of the disease and regresses within a week, responding to antihistamines. Of note, clinically similar rashes can be caused by drugs. Histologically, the lesions show dermal edema and a mild perivascular lymphocytic infiltrate, sometimes admixed with eosinophils.

Chilblainlike Lesions—Chilblainlike lesions (CBLLs) account for 19% of skin manifestations associated with COVID-19¹³ and present as erythematous-purplish, edematous lesions that can be mildly pruritic or painful, appearing on the toes—COVID toes—and more rarely the fingers (Figure 2). They were seen epidemically during the first pandemic wave (2020 lockdown) in several countries, and clinically are very similar to, if not indistinguishable from, idiopathic chilblains, but are not necessarily associated with cold exposure. They appear in young, generally healthy patients or those with mild COVID-19 symptoms 2 to 4 weeks after symptom onset. They regress spontaneously or under local corticosteroid treatment within a few days or weeks. Histologically, CBLLs are indistinguishable from chilblains of other origins, namely idiopathic (seasonal) ones. They manifest with necrosis of epidermal keratinocytes; dermal edema that may be severe, leading to the development of subepidermal pseudobullae; a rather dense perivascular and perieccrine gland lymphocytic infiltrate; and sometimes with vascular lesions (eg, edema of endothelial cells, microthromboses of dermal capillaries and venules, fibrinoid deposits within the wall of dermal venules)(Figure 3).^16-18 Most patients (>80%) with CBLLs have negative serologic or polymerase chain reaction tests for SARS-CoV-2,¹⁹ which generated a lively debate about the role of SARS-CoV-2 in the genesis of CBLLs. According to some authors, SARS-CoV-2 plays no direct role, and CBLLs would occur in young people who sit or walk barefoot on cold floors at home during confinement.^20-23 Remarkably, CBLLs appeared in patients with no history of chilblains during a season that was not particularly cold, namely in France or in southern California, where their incidence was much higher compared to the same time period of prior years. Some reports have supported a direct role for the virus based on questionable observations of the virus within skin lesions (eg, sweat glands, endothelial cells) by immunohistochemistry, electron microscopy, and/or in situ hybridization.^17,24,25 A more satisfactory hypothesis would involve the role of a strong innate immunity leading to elimination of the virus before the development of specific antibodies via the increased production of type 1 interferon (IFN-1); this would affect the vessels, causing CBLLs. This mechanism would be similar to the one observed in some interferonopathies (eg, Aicardi-Goutières syndrome), also characterized by IFN-1 hypersecretion and chilblains.^26-29 According to this hypothesis, CBLLs should be considered a paraviral rash similar to other skin manifestations associated with COVID-19.³⁰

Acro-ischemia—Acro-ischemia livedoid lesions account for 1% to 6% of skin manifestations and comprise lesions of livedo (either reticulated or racemosa); necrotic acral bullae; and gangrenous necrosis of the extremities, especially the toes. The livedoid lesions most often appear within 15 days of COVID-19 symptom onset, and the purpuric lesions somewhat later (2–4 weeks); they mainly affect adult patients, last about 10 days, and are the hallmark of severe infection, presumably related to microthromboses of the cutaneous capillaries (endothelial dysfunction, prothrombotic state, elevated D-dimers). Histologically, they show capillary thrombosis and dermoepidermal necrosis (Figure 4).

Other Reported Polymorphic or Atypical Rashes—Erythema multiforme–like eruptions may appear before other COVID-19 symptoms and manifest as reddish-purple, nearly symmetric, diffuse, occasionally targetoid bullous or necrotic macules. The eruptions mainly affect adults and most often are seen on the palms, elbows, knees, and sometimes the mucous membranes. The rash regresses in 1 to 3 weeks without scarring and represents a delayed cutaneous hypersensitivity reaction. Histologically, the lesions show vacuolization of basal epidermal keratinocytes, keratinocyte necrosis, dermoepidermal detachment, a variably dense dermal T-lymphocytic infiltrate, and red blood cell extravasation (Figure 5).

Leukocytoclastic vasculitis may be generalized or localized. It manifests clinically by petechial/purpuric maculopapules, especially on the legs, mainly in elderly patients with COVID-19. Histologically, the lesions show necrotizing changes of dermal postcapillary venules, neutrophilic perivascular inflammation, red blood cell extravasation, and occasionally vascular IgA deposits by direct immunofluorescence examination. The course usually is benign.

The incidence of pityriasis rosea and of clinically similar rashes (referred to as “pityriasis rosea–like”) increased 5-fold during the COVID-19 pandemic.^31,32 These dermatoses manifest with erythematous, scaly, circinate plaques, typically with an initial herald lesion followed a few days later by smaller erythematous macules. Histologically, the lesions comprise a spongiform dermatitis with intraepidermal exocytosis of red blood cells and a mild to moderate dermal lymphocytic infiltrate.

Erythrodysesthesia, or hand-foot syndrome, manifests with edematous erythema and palmoplantar desquamation accompanied by a burning sensation or pain. This syndrome is known as an adverse effect of some chemotherapies because of the associated drug toxicity and sweat gland inflammation; it was observed in 40% of 666 COVID-19–positive patients with mild to moderate pneumonitis.³³

“COVID nose” is a rare cutaneous manifestation characterized by nasal pigmentation comprising multiple coalescent frecklelike macules on the tip and wings of the nose and sometimes the malar areas. These lesions predominantly appear in women aged 25 to 65 years and show on average 23 days after onset of COVID-19, which is usually mild. This pigmentation is similar to pigmentary changes after infection with chikungunya; it can be treated with depigmenting products such as azelaic acid and hydroquinone cream with sunscreen use, and it regresses in 2 to 4 months.³⁴

Telogen effluvium (excessive and temporary shedding of normal telogen club hairs of the entire scalp due to the disturbance of the hair cycle) is reportedly frequent in patients (48%) 1 month after COVID-19 infection, but it may appear later (after 12 weeks).³⁵ Alopecia also is frequently reported during long (or postacute) COVID-19 (ie, the symptomatic disease phase past the acute 4 weeks’ stage of the infection) and shows a female predominance³⁶; it likely represents the telogen effluvium seen 90 days after a severe illness. Trichodynia (pruritus, burning, pain, or paresthesia of the scalp) also is reportedly common (developing in more than 58% of patients) and is associated with telogen effluvium in 44% of cases. Several cases of alopecia areata (AA) triggered or aggravated by COVID-19 also have been reported^37,38; they could be explained by the “cytokine storm” triggered by the infection, involving T and B lymphocytes; plasmacytoid dendritic cells; natural killer cells with oversecretion of IL-6, IL-4, tumor necrosis factor α, and IFN type I; and a cytotoxic reaction associated with loss of the immune privilege of hair follicles.

Nail Manifestations

The red half-moon nail sign is an asymptomatic purplish-red band around the distal margin of the lunula that affects some adult patients with COVID-19.³⁹ It appears shortly after onset of symptoms, likely the manifestation of vascular inflammation in the nail bed, and regresses slowly after approximately 1 week.⁴⁰ Beau lines are transverse grooves in the nail plate due to the temporary arrest of the proximal nail matrix growth accompanying systemic illnesses; they appear approximately 2 to 3 weeks after the onset of COVID-19.⁴¹ Furthermore, nail alterations can be caused by drugs used to treat COVID-19, such as longitudinal melanonychia due to treatment with hydroxychloroquine or fluorescence of the lunula or nail plate due to treatment with favipiravir.⁴²

Multisystem Inflammatory Syndrome

Multisystem inflammatory syndrome (MIS) is clinically similar to Kawasaki disease; it typically affects children⁴³ and more rarely adults with COVID-19. It manifests with fever, weakness, and biological inflammation and also frequently with skin lesions (72%), which are polymorphous and include morbilliform rash (27%); urticaria (24%); periorbital edema (24%); nonspecific erythema (21.2%); retiform purpura (18%); targetoid lesions (15%); malar rash (15.2%); and periareolar erythema (6%).⁴⁴ Compared to Kawasaki disease, MIS affects slightly older children (mean age, 8.5 vs 3 years) and more frequently includes cardiac and gastrointestinal manifestations; the mortality rate also is slightly higher (2% vs 0.17%).⁴⁵

Confirmed COVID-19 Infection

At the beginning of the pandemic, skin manifestations were reported in patients who were suspected of having COVID-19 but did not always have biological confirmation of SARS-CoV-2 infection due to the unavailability of diagnostic tests or the physical impossibility of testing. However, subsequent studies have confirmed that most of these dermatoses were indeed associated with COVID-19 infection.^9,46 For example, a study of 655 patients with confirmed COVID-19 infection reported maculopapular (38%), vascular (22%), urticarial (15%), and vesicular (15%) rashes; erythema multiforme or Stevens-Johnson–like syndrome (3%, often related to the use of hydroxychloroquine); generalized pruritus (1%); and MIS (0.5%). The study confirmed that CBLLs were mostly seen in young patients with mild disease, whereas livedo (fixed rash) and retiform purpura occurred in older patients with a guarded prognosis.⁴⁶

Remarkably, most dermatoses associated with SARS-CoV-2 infection were reported during the initial waves of the pandemic, which were due to the α and δ viral variants. These manifestations were reported more rarely when the ο variant was predominant, even though most patients (63%) who developed CBLLs in the first wave also developed them during the second pandemic wave.⁴⁷ This decrease in the incidence of COVID-19–associated dermatoses could be because of the lower pathogenicity of the o variant,³ a lower tropism for the skin, and variations in SARS-CoV-2 antigenicity that would induce a different immunologic response, combined with an increasingly stronger herd immunity compared to the first pandemic waves achieved through vaccination and spontaneous infections in the population. Additional reasons may include different baseline characteristics in patients hospitalized with COVID-19 (regarding comorbidities, disease severity, and received treatments), and the possibility that some of the initially reported COVID-19–associated skin manifestations could have been produced by different etiologic agents.⁴⁸ In the last 2 years, COVID-19–related skin manifestations have been reported mainly as adverse events to COVID-19 vaccination.

CUTANEOUS ADVERSE EFFECTS OF DRUGS USED TO TREAT COVID-19

Prior to the advent of vaccines and specific treatments for SARS-CoV-2, various drugs were used—namely hydroxychloroquine, ivermectin, and tocilizumab—that did not prove efficacious and caused diverse adverse effects, including cutaneous eruptions such as urticaria, maculopapular eruptions, erythema multiforme or Stevens-Johnson syndrome, vasculitis, longitudinal melanonychia, and acute generalized exanthematous pustulosis.^49,50 Nirmatrelvir 150 mg–ritonavir 100 mg, which was authorized for emergency use by the US Food and Drug Administration for the treatment of COVID-19, is a viral protease inhibitor blocking the replication of the virus. Ritonavir can induce pruritus, maculopapular rash, acne, Stevens-Johnson syndrome, and toxic epidermal necrolysis; of note, these effects have been observed following administration of ritonavir for treatment of HIV at higher daily doses and for much longer periods of time compared with treatment of COVID-19 (600–1200 mg vs 200 mg/d, respectively). These cutaneous drug side effects are clinically similar to the manifestations caused either directly or indirectly by SARS-CoV-2 infection; therefore, it may be difficult to differentiate them.

DERMATOSES DUE TO PROTECTIVE DEVICES

Dermatoses due to personal protective equipment such as masks or face shields affected the general population and mostly health care professionals⁵¹; 54.4% of 879 health care professionals in one study reported such events.⁵² These dermatoses mainly include contact dermatitis of the face (nose, forehead, and cheeks) of irritant or allergic nature (eg, from preservatives releasing formaldehyde contained in masks and protective goggles). They manifest with skin dryness; desquamation; maceration; fissures; or erosions or ulcerations of the cheeks, forehead, and nose. Cases of pressure urticaria also have been reported. Irritant dermatitis induced by the frequent use of disinfectants (eg, soaps, hydroalcoholic sanitizing gels) also can affect the hands. Allergic hand dermatitis can be caused by medical gloves.

The term maskne (or mask acne) refers to a variety of mechanical acne due to the prolonged use of surgical masks (>4 hours per day for ≥6 weeks); it includes cases of de novo acne and cases of pre-existing acne aggravated by wearing a mask. Maskne is characterized by acne lesions located on the facial area covered by the mask (Figure 6). It is caused by follicular occlusion; increased sebum secretion; mechanical stress (pressure, friction); and dysbiosis of the microbiome induced by changes in heat, pH, and humidity. Preventive measures include application of noncomedogenic moisturizers or gauze before wearing the mask as well as facial cleansing with appropriate nonalcoholic products. Similar to acne, rosacea often is aggravated by prolonged wearing of surgical masks (mask rosacea).^53,54

DERMATOSES REVEALED OR AGGRAVATED BY COVID-19

Exacerbation of various skin diseases has been reported after infection with SARS-CoV-2.⁵⁵ Psoriasis and acrodermatitis continua of Hallopeau,⁵⁶ which may progress into generalized, pustular, or erythrodermic forms,⁵⁷ have been reported; the role of hydroxychloroquine and oral corticosteroids used for the treatment of COVID-19 has been suspected.⁵⁷ Atopic dermatitis patients—26% to 43%—have experienced worsening of their disease after symptomatic COVID-19 infection.⁵⁸ The incidence of herpesvirus infections, including herpes zoster, increased during the pandemic.⁵⁹ Alopecia areata relapses occurred in 42.5% of 392 patients with preexisting disease within 2 months of COVID-19 onset in one study,⁶⁰ possibly favored by the psychological stress; however, some studies have not confirmed the aggravating role of COVID-19 on alopecia areata.⁶¹ Lupus erythematosus, which may relapse in the form of Rowell syndrome,⁶² and livedoid vasculopathy⁶³ also have been reported following COVID-19 infection.

SKIN MANIFESTATIONS ASSOCIATED WITH COVID-19 VACCINES

In parallel with the rapid spread of COVID-19 vaccination,⁴ an increasing number of skin manifestations has been observed following vaccination; these dermatoses now are more frequently reported than those related to natural SARS-CoV-2 infection.^64-70 Vaccine-induced skin manifestations have a reported incidence of approximately 4% and show a female predominance.⁶⁵ Most of them (79%) have been reported in association with messenger RNA (mRNA)–based vaccines, which have been the most widely used; however, the frequency of side effects would be lower after mRNA vaccines than after inactivated virus-based vaccines. Eighteen percent occurred after the adenoviral vector vaccine, and 3% after the inactivated virus vaccine.⁷⁰ Fifty-nine percent were observed after the first dose. They are clinically polymorphous and generally benign, regressing spontaneously after a few days, and they should not constitute a contraindication to vaccination.Interestingly, many skin manifestations are similar to those associated with natural SARS-CoV-2 infection; however, their frequency and severity does not seem to depend on whether the patients had developed skin reactions during prior SARS-CoV-2 infection. These reactions have been classified into several types:

• Immediate local reactions at the injection site: pain, erythema, or edema represent the vast majority (96%) of reactions to vaccines. They appear within 7 days after vaccination (average, 1 day), slightly more frequently (59%) after the first dose. They concern mostly young patients and are benign, regressing in 2 to 3 days.⁷⁰
 

• Delayed local reactions: characterized by pain or pruritus, erythema, and skin induration mimicking cellulitis (COVID arm) and represent 1.7% of postvaccination reactions. They correspond to a delayed hypersensitivity reaction and appear approximately 7 days after vaccination, most often after the first vaccine dose (75% of cases), which is almost invariably mRNA based.⁷⁰

• Urticarial reactions corresponding to an immediate (type 1) hypersensitivity reaction: constitute 1% of postvaccination reactions, probably due to an allergy to vaccine ingredients. They appear on average 1 day after vaccination, almost always with mRNA vaccines.⁷⁰

• Angioedema: characterized by mucosal or subcutaneous edema and constitutes 0.5% of postvaccination reactions. It is a potentially serious reaction that appears on average 12 hours after vaccination, always with an mRNA-based vaccine.⁷⁰

• Morbilliform rash: represents delayed hypersensitivity reactions (0.1% of postvaccination reactions) that appear mostly after the first dose (72%), on average 3 days after vaccination, always with an mRNA-based vaccine.⁷⁰

• Herpes zoster: usually develops after the first vaccine dose in elderly patients (69% of cases) on average 4 days after vaccination and constitutes 0.1% of postvaccination reactions.⁷¹

• Bullous diseases: mainly bullous pemphigoid (90%) and more rarely pemphigus (5%) or bullous erythema pigmentosum (5%). They appear in elderly patients on average 7 days after vaccination and constitute 0.04% of postvaccination reactions.⁷²

• Chilblainlike lesions: several such cases have been reported so far⁷³; they constitute 0.03% of postvaccination reactions.⁷⁰ Clinically, they are similar to those associated with natural COVID-19; they appear mostly after the first dose (64%), on average 5 days after vaccination with the mRNA or adenovirus vaccine, and show a female predominance. The appearance of these lesions in vaccinated patients, who are a priori not carriers of the virus, strongly suggests that CBLLs are due to the immune reaction against SARS-CoV-2 rather than to a direct effect of this virus on the skin, which also is a likely scenario with regards to other skin manifestations seen during the successive COVID-19 epidemic waves.^73-75

• Reactions to hyaluronic acid–containing cosmetic fillers: erythema, edema, and potentially painful induration at the filler injection sites. They constitute 0.04% of postvaccination skin reactions and appear 24 hours after vaccination with mRNA-based vaccines, equally after the first or second dose.⁷⁶

• Pityriasis rosea–like rash: most occur after the second dose of mRNA-based vaccines (0.023% of postvaccination skin reactions).⁷⁰

• Severe reactions: these include acute generalized exanthematous pustulosis⁷⁷ and Stevens-Johnson syndrome.⁷⁸ One case of each has been reported after the adenoviral vector vaccine 3 days after vaccination.

Other more rarely observed manifestations include reactivation/aggravation or de novo appearance of inflammatory dermatoses such as psoriasis,^79,80 leukocytoclastic vasculitis,^81,82 lymphocytic⁸³ or urticarial⁸⁴ vasculitis, Sweet syndrome,⁸⁵ lupus erythematosus, dermatomyositis,^86,87 alopecia,^37,88 infection with Trichophyton rubrum,⁸⁹ Grover disease,⁹⁰ and lymphomatoid reactions (such as recurrences of cutaneous T-cell lymphomas [CD30⁺], and de novo development of lymphomatoid papulosis).⁹¹

FINAL THOUGHTS

COVID-19 is associated with several skin manifestations, even though the causative role of SARS-CoV-2 has remained elusive. These dermatoses are highly polymorphous, mostly benign, and usually spontaneously regressive, but some of them reflect severe infection. They mostly were described during the first pandemic waves, reported in several national and international registries, which allowed for their morphological classification. Currently, cutaneous adverse effects of vaccines are the most frequently reported dermatoses associated with SARS-CoV-2, and it is likely that they will continue to be observed while COVID-19 vaccination lasts. Hopefully the end of the COVID-19 pandemic is near. In January 2023, the International Health Regulations Emergency Committee of the World Health Organization acknowledged that the COVID-19 pandemic may be approaching an inflexion point, and even though the event continues to constitute a public health emergency of international concern, the higher levels of population immunity achieved globally through infection and/or vaccination may limit the impact of SARS-CoV-2 on morbidity and mortality. However, there is little doubt that this virus will remain a permanently established pathogen in humans and animals for the foreseeable future.⁹² Therefore, physicians—especially dermatologists—should be aware of the various skin manifestations associated with COVID-19 so they can more efficiently manage their patients.

Scent-detecting dogs have long been used to sniff out medical conditions ranging from low blood sugar and cancer to malaria, impending seizures, and migraines – not to mention explosives and narcotics.

Recently, the sensitivity of the canine nose has been tested as a strategy for screening for SARS-CoV-2 infection in schoolchildren showing no outward symptoms of the virus. A pilot study led by Carol A. Glaser, DVM, MD, of the California Department of Public Health in Richmond, found that trained dogs had an accuracy of more than 95% for detecting the odor of volatile organic compounds, or VOCs, produced by COVID-infected individuals.

California Department of Public Health

The authors believe that odor-based diagnosis with dogs could eventually provide a rapid, inexpensive, and noninvasive way to screen large groups for COVID-19 without the need for antigen testing.

“This is a new program with research ongoing, so it would be premature to consider it from a consumer’s perspective,” Dr. Glaser said in an interview. “However, the data look promising and we are hopeful we can continue to pilot various programs in various settings to see where, and if, dogs can be used for biomedical detection.”
 

In the lab and in the field

In a study published online in JAMA Pediatrics, Dr. Glaser’s group found that after 2 months’ training on COVID-19 scent samples in the laboratory, the dogs detected the presence of the virus more than 95% of the time. Antigen tests were used as a comparative reference.

In medical terms, the dogs achieved a greater than 95% accuracy on two important measures of effectiveness: sensitivity – a test’s ability to correctly detect the positive presence of disease – and specificity – the ability of a test to accurately rule out the presence of disease and identify as negative an uninfected person.

Next, the researchers piloted field tests in 50 visits at 27 schools from April 1 to May 25, 2022, to compare dogs’ detection ability with that of standard laboratory antigen testing. Participants in the completely voluntary screening numbered 1,558 and ranged in age from 9 to 17 years. Of these, 56% were girls and 89% were students. Almost 70% were screened at least twice.

Overall, the field test compared 3,897 paired antigen-vs.-dog screenings. The dogs accurately signaled the presence of 85 infections and ruled out 3,411 infections, for an overall accuracy of 90%. In 383 cases, however, they inaccurately signaled the presence of infection (false positives) and missed 18 actual infections (false negatives). That translated to a sensitivity in the field of 83%, considerably lower than that of their lab performance.

Direct screening of individuals with dogs outside of the lab involved circumstantial factors that likely contributed to decreased sensitivity and specificity, the authors acknowledged. These included such distractions as noise and the presence of excitable young children as well environmental conditions such as wind and other odors. What about dog phobia and dog hair allergy? “Dog screening takes only a few seconds per student and the dogs do not generally touch the participant as they run a line and sniff at ankles,” Dr. Glaser explained.

As for allergies, the rapid, ankle-level screening occurred in outdoor settings. “The chance of allergies is very low. This would be similar to someone who is out walking on the sidewalk and walks by a dog,” Dr. Glaser said.

Last year, a British trial of almost 4,000 adults tested six dogs trained to detect differences in VOCs between COVID-infected and uninfected individuals. Given samples from both groups, the dogs were able to distinguish between infected and uninfected samples with a sensitivity for detecting the virus ranging from 82% to 94% and a specificity for ruling it out of 76% to 92%. And they were able to smell the VOCs even when the viral load was low. The study also tested organic sensors, which proved even more accurate than the canines.

According to lead author James G. Logan, PhD, a disease control expert at the London School of Hygiene & Tropical Medicine in London, “Odour-based diagnostics using dogs and/or sensors may prove a rapid and effective tool for screening large numbers of people. Mathematical modelling suggests that dog screening plus a confirmatory PCR test could detect up to 89% of SARS-CoV-2 infections, averting up to 2.2 times as much transmission compared to isolation of symptomatic individuals only.”

Funding was provided by the Centers for Disease Control and Prevention Foundation (CDCF) to Early Alert Canines for the purchase and care of the dogs and the support of the handlers and trainers. The CDCF had no other role in the study. Coauthor Carol A. Edwards of Early Alert Canines reported receiving grants from the CDCF.

Scent-detecting dogs have long been used to sniff out medical conditions ranging from low blood sugar and cancer to malaria, impending seizures, and migraines – not to mention explosives and narcotics.

Recently, the sensitivity of the canine nose has been tested as a strategy for screening for SARS-CoV-2 infection in schoolchildren showing no outward symptoms of the virus. A pilot study led by Carol A. Glaser, DVM, MD, of the California Department of Public Health in Richmond, found that trained dogs had an accuracy of more than 95% for detecting the odor of volatile organic compounds, or VOCs, produced by COVID-infected individuals.

California Department of Public Health

The authors believe that odor-based diagnosis with dogs could eventually provide a rapid, inexpensive, and noninvasive way to screen large groups for COVID-19 without the need for antigen testing.

“This is a new program with research ongoing, so it would be premature to consider it from a consumer’s perspective,” Dr. Glaser said in an interview. “However, the data look promising and we are hopeful we can continue to pilot various programs in various settings to see where, and if, dogs can be used for biomedical detection.”
 

In the lab and in the field

In a study published online in JAMA Pediatrics, Dr. Glaser’s group found that after 2 months’ training on COVID-19 scent samples in the laboratory, the dogs detected the presence of the virus more than 95% of the time. Antigen tests were used as a comparative reference.

In medical terms, the dogs achieved a greater than 95% accuracy on two important measures of effectiveness: sensitivity – a test’s ability to correctly detect the positive presence of disease – and specificity – the ability of a test to accurately rule out the presence of disease and identify as negative an uninfected person.

Next, the researchers piloted field tests in 50 visits at 27 schools from April 1 to May 25, 2022, to compare dogs’ detection ability with that of standard laboratory antigen testing. Participants in the completely voluntary screening numbered 1,558 and ranged in age from 9 to 17 years. Of these, 56% were girls and 89% were students. Almost 70% were screened at least twice.

Overall, the field test compared 3,897 paired antigen-vs.-dog screenings. The dogs accurately signaled the presence of 85 infections and ruled out 3,411 infections, for an overall accuracy of 90%. In 383 cases, however, they inaccurately signaled the presence of infection (false positives) and missed 18 actual infections (false negatives). That translated to a sensitivity in the field of 83%, considerably lower than that of their lab performance.

Direct screening of individuals with dogs outside of the lab involved circumstantial factors that likely contributed to decreased sensitivity and specificity, the authors acknowledged. These included such distractions as noise and the presence of excitable young children as well environmental conditions such as wind and other odors. What about dog phobia and dog hair allergy? “Dog screening takes only a few seconds per student and the dogs do not generally touch the participant as they run a line and sniff at ankles,” Dr. Glaser explained.

As for allergies, the rapid, ankle-level screening occurred in outdoor settings. “The chance of allergies is very low. This would be similar to someone who is out walking on the sidewalk and walks by a dog,” Dr. Glaser said.

Last year, a British trial of almost 4,000 adults tested six dogs trained to detect differences in VOCs between COVID-infected and uninfected individuals. Given samples from both groups, the dogs were able to distinguish between infected and uninfected samples with a sensitivity for detecting the virus ranging from 82% to 94% and a specificity for ruling it out of 76% to 92%. And they were able to smell the VOCs even when the viral load was low. The study also tested organic sensors, which proved even more accurate than the canines.

According to lead author James G. Logan, PhD, a disease control expert at the London School of Hygiene & Tropical Medicine in London, “Odour-based diagnostics using dogs and/or sensors may prove a rapid and effective tool for screening large numbers of people. Mathematical modelling suggests that dog screening plus a confirmatory PCR test could detect up to 89% of SARS-CoV-2 infections, averting up to 2.2 times as much transmission compared to isolation of symptomatic individuals only.”

Funding was provided by the Centers for Disease Control and Prevention Foundation (CDCF) to Early Alert Canines for the purchase and care of the dogs and the support of the handlers and trainers. The CDCF had no other role in the study. Coauthor Carol A. Edwards of Early Alert Canines reported receiving grants from the CDCF.

Scent-detecting dogs have long been used to sniff out medical conditions ranging from low blood sugar and cancer to malaria, impending seizures, and migraines – not to mention explosives and narcotics.

Recently, the sensitivity of the canine nose has been tested as a strategy for screening for SARS-CoV-2 infection in schoolchildren showing no outward symptoms of the virus. A pilot study led by Carol A. Glaser, DVM, MD, of the California Department of Public Health in Richmond, found that trained dogs had an accuracy of more than 95% for detecting the odor of volatile organic compounds, or VOCs, produced by COVID-infected individuals.

California Department of Public Health

The authors believe that odor-based diagnosis with dogs could eventually provide a rapid, inexpensive, and noninvasive way to screen large groups for COVID-19 without the need for antigen testing.

“This is a new program with research ongoing, so it would be premature to consider it from a consumer’s perspective,” Dr. Glaser said in an interview. “However, the data look promising and we are hopeful we can continue to pilot various programs in various settings to see where, and if, dogs can be used for biomedical detection.”
 

In the lab and in the field

In a study published online in JAMA Pediatrics, Dr. Glaser’s group found that after 2 months’ training on COVID-19 scent samples in the laboratory, the dogs detected the presence of the virus more than 95% of the time. Antigen tests were used as a comparative reference.

In medical terms, the dogs achieved a greater than 95% accuracy on two important measures of effectiveness: sensitivity – a test’s ability to correctly detect the positive presence of disease – and specificity – the ability of a test to accurately rule out the presence of disease and identify as negative an uninfected person.

Next, the researchers piloted field tests in 50 visits at 27 schools from April 1 to May 25, 2022, to compare dogs’ detection ability with that of standard laboratory antigen testing. Participants in the completely voluntary screening numbered 1,558 and ranged in age from 9 to 17 years. Of these, 56% were girls and 89% were students. Almost 70% were screened at least twice.

Overall, the field test compared 3,897 paired antigen-vs.-dog screenings. The dogs accurately signaled the presence of 85 infections and ruled out 3,411 infections, for an overall accuracy of 90%. In 383 cases, however, they inaccurately signaled the presence of infection (false positives) and missed 18 actual infections (false negatives). That translated to a sensitivity in the field of 83%, considerably lower than that of their lab performance.

Direct screening of individuals with dogs outside of the lab involved circumstantial factors that likely contributed to decreased sensitivity and specificity, the authors acknowledged. These included such distractions as noise and the presence of excitable young children as well environmental conditions such as wind and other odors. What about dog phobia and dog hair allergy? “Dog screening takes only a few seconds per student and the dogs do not generally touch the participant as they run a line and sniff at ankles,” Dr. Glaser explained.

As for allergies, the rapid, ankle-level screening occurred in outdoor settings. “The chance of allergies is very low. This would be similar to someone who is out walking on the sidewalk and walks by a dog,” Dr. Glaser said.

Last year, a British trial of almost 4,000 adults tested six dogs trained to detect differences in VOCs between COVID-infected and uninfected individuals. Given samples from both groups, the dogs were able to distinguish between infected and uninfected samples with a sensitivity for detecting the virus ranging from 82% to 94% and a specificity for ruling it out of 76% to 92%. And they were able to smell the VOCs even when the viral load was low. The study also tested organic sensors, which proved even more accurate than the canines.

According to lead author James G. Logan, PhD, a disease control expert at the London School of Hygiene & Tropical Medicine in London, “Odour-based diagnostics using dogs and/or sensors may prove a rapid and effective tool for screening large numbers of people. Mathematical modelling suggests that dog screening plus a confirmatory PCR test could detect up to 89% of SARS-CoV-2 infections, averting up to 2.2 times as much transmission compared to isolation of symptomatic individuals only.”

Funding was provided by the Centers for Disease Control and Prevention Foundation (CDCF) to Early Alert Canines for the purchase and care of the dogs and the support of the handlers and trainers. The CDCF had no other role in the study. Coauthor Carol A. Edwards of Early Alert Canines reported receiving grants from the CDCF.

BOSTON – The neurologic symptoms of long COVID appear to be explained by a phenomenon known as antigenic imprinting, which involves a misdirected immune response to the SARS-CoV2 virus, according to a collaborative study presented at the 2023 annual meeting of the American Academy of Neurology.

Already documented in several other viral infections, such as influenza and human immunodeficiency virus, antigenic imprinting results in production of antibodies to previously encountered viral infections rather than to the immediate threat, according to Marianna Spatola, MD, PhD, a research fellow at the Ragon Institute, Harvard University, Cambridge, Mass.
 

Original antigenic sin

In the case of persistent neurologic symptoms after COVID, a condition known as neuroPASC (neurological postacute sequelae of SARS-CoV2 infection), antibodies produced for previously encountered coronaviruses rather than for SARS-CoV2 might explain most or all cases, according to the data Dr. Spatola presented.

The evidence for this explanation was drawn from a study of 112 patients evaluated months after an acute episode of COVID-19. Of these, 18 patients had persistent neurologic dysfunction. When compared with the 94 whose infection resolved without sequelae, the patients with prolonged neurologic impairments had relatively low systemic antibody response to SARS-CoV2. However, they showed relatively high antibody responses against other coronaviruses.

This is a pattern consistent with antigenic imprinting, a concept first described more than 60 years ago as original antigenic sin. When the immune system becomes imprinted with an antigen from the first encountered virus from a family of pathogens, it governs all subsequent antibody responses, according to several published studies that have described and evaluated this concept.
 

Additional evidence

In Dr. Spatola’s study, other differences, particularly in regard to the cerebrospinal fluid (CSF), further supported the role of antigenic imprinting as a cause of neuroPASC. For one, those with elevated immune responses to other common coronaviruses rather than SARS-CoV2 in the CSF relative to the periphery were more likely to have a bad outcome in regard to neurologic symptoms.

Moreover, the CSF in neuroPASC patients “was characterized by increased IgG1 and absence of IgM, suggesting compartmentalized humoral responses within the CSF through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier rather than through intrathecal synthesis,” Dr. Spatola reported.

In the case of COVID-19, the propensity for antigenic imprinting is not difficult to understand.

“The common cold coronaviruses are pretty similar to SARS-CoV2, but they are not exactly the same,” Dr. Spatola said. Her work and studies by others suggest that when antigenic imprinting occurs, “it prevents full maturation of the antibody response.”

NeuroPASC is one of many manifestations of long COVID, but Dr. Spatola pointed out that the immune response in the CSF is unique and the causes of prolonged neurologic impairment after COVID-19 are likely to involve different mechanisms than other long-COVID symptoms.

“Antibodies in the brain are functionally different,” said Dr. Spatola, noting for example that antibody-directed defenses against viral threats show a greater relative reliance on phagocytosis. This might become important in the development of therapeutics for neurologic symptoms of long COVID.
 

A different phenomenon

The manifestations of neuroPASC are heterogeneous and can include confusion, cognitive dysfunction, headache, encephalitis, and other impairments. Neurologic symptoms occur during acute SARS-CoV2 infections, but neuroPASC appears to be a different phenomenon. These symptoms, which develop after the initial respiratory disease has resolved, were attributed by Dr. Spatola to persistent inflammation that is not necessarily directly related to ongoing infection.

“The reason why some patients develop neuroPASC is unknown, but I think the evidence has pointed to a role for the immune system rather than the virus itself,” Dr. Spatola said.

Currently, neuroPASC is a clinical diagnosis but Dr. Spatola and her coinvestigators are conducting research to identify biomarkers. A viable diagnostic test is not expected imminently. They have identified 150 different features with potential relevance to neuroPASC.

In their comparison of those who did relative to those who did not develop neuroPASC, the initial studies were undertaken 2-4 months after the acute COVID-19 symptoms had resolved. The patients with neuroPASC and those without neurologic sequelae have now been followed for 6-8 months, which Dr. Spatola said was too short to draw firm conclusions about outcomes.
 

An evolving concept

Despite the small sample size of this study, these are “very interesting data” for considering the pathogenesis of neuroPASC, which is “a concept that is still evolving,” according to Natalia S. Rost, MD, chief of the stroke division, department of neurology, Massachusetts General Hospital, Boston.

Applied to SARS-CoV2, the concept of original antigenic sin “is new” but Dr. Rost said that it might help differentiate neuroPASC from acute neurologic symptoms of COVID-19, which include stroke. She indicated that the work performed by Dr. Spatola and others might eventually explain the pathology while leading to treatment strategies. She cautioned that the concepts explored in this study “need to be further developed” through larger sample sizes and the exploration of other variables that support the hypothesis.

Dr. Spatola and Dr. Rost report no potential conflicts of interest.

BOSTON – The neurologic symptoms of long COVID appear to be explained by a phenomenon known as antigenic imprinting, which involves a misdirected immune response to the SARS-CoV2 virus, according to a collaborative study presented at the 2023 annual meeting of the American Academy of Neurology.

Already documented in several other viral infections, such as influenza and human immunodeficiency virus, antigenic imprinting results in production of antibodies to previously encountered viral infections rather than to the immediate threat, according to Marianna Spatola, MD, PhD, a research fellow at the Ragon Institute, Harvard University, Cambridge, Mass.
 

Original antigenic sin

In the case of persistent neurologic symptoms after COVID, a condition known as neuroPASC (neurological postacute sequelae of SARS-CoV2 infection), antibodies produced for previously encountered coronaviruses rather than for SARS-CoV2 might explain most or all cases, according to the data Dr. Spatola presented.

The evidence for this explanation was drawn from a study of 112 patients evaluated months after an acute episode of COVID-19. Of these, 18 patients had persistent neurologic dysfunction. When compared with the 94 whose infection resolved without sequelae, the patients with prolonged neurologic impairments had relatively low systemic antibody response to SARS-CoV2. However, they showed relatively high antibody responses against other coronaviruses.

This is a pattern consistent with antigenic imprinting, a concept first described more than 60 years ago as original antigenic sin. When the immune system becomes imprinted with an antigen from the first encountered virus from a family of pathogens, it governs all subsequent antibody responses, according to several published studies that have described and evaluated this concept.
 

Additional evidence

In Dr. Spatola’s study, other differences, particularly in regard to the cerebrospinal fluid (CSF), further supported the role of antigenic imprinting as a cause of neuroPASC. For one, those with elevated immune responses to other common coronaviruses rather than SARS-CoV2 in the CSF relative to the periphery were more likely to have a bad outcome in regard to neurologic symptoms.

Moreover, the CSF in neuroPASC patients “was characterized by increased IgG1 and absence of IgM, suggesting compartmentalized humoral responses within the CSF through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier rather than through intrathecal synthesis,” Dr. Spatola reported.

In the case of COVID-19, the propensity for antigenic imprinting is not difficult to understand.

“The common cold coronaviruses are pretty similar to SARS-CoV2, but they are not exactly the same,” Dr. Spatola said. Her work and studies by others suggest that when antigenic imprinting occurs, “it prevents full maturation of the antibody response.”

NeuroPASC is one of many manifestations of long COVID, but Dr. Spatola pointed out that the immune response in the CSF is unique and the causes of prolonged neurologic impairment after COVID-19 are likely to involve different mechanisms than other long-COVID symptoms.

“Antibodies in the brain are functionally different,” said Dr. Spatola, noting for example that antibody-directed defenses against viral threats show a greater relative reliance on phagocytosis. This might become important in the development of therapeutics for neurologic symptoms of long COVID.
 

A different phenomenon

The manifestations of neuroPASC are heterogeneous and can include confusion, cognitive dysfunction, headache, encephalitis, and other impairments. Neurologic symptoms occur during acute SARS-CoV2 infections, but neuroPASC appears to be a different phenomenon. These symptoms, which develop after the initial respiratory disease has resolved, were attributed by Dr. Spatola to persistent inflammation that is not necessarily directly related to ongoing infection.

“The reason why some patients develop neuroPASC is unknown, but I think the evidence has pointed to a role for the immune system rather than the virus itself,” Dr. Spatola said.

Currently, neuroPASC is a clinical diagnosis but Dr. Spatola and her coinvestigators are conducting research to identify biomarkers. A viable diagnostic test is not expected imminently. They have identified 150 different features with potential relevance to neuroPASC.

In their comparison of those who did relative to those who did not develop neuroPASC, the initial studies were undertaken 2-4 months after the acute COVID-19 symptoms had resolved. The patients with neuroPASC and those without neurologic sequelae have now been followed for 6-8 months, which Dr. Spatola said was too short to draw firm conclusions about outcomes.
 

An evolving concept

Despite the small sample size of this study, these are “very interesting data” for considering the pathogenesis of neuroPASC, which is “a concept that is still evolving,” according to Natalia S. Rost, MD, chief of the stroke division, department of neurology, Massachusetts General Hospital, Boston.

Applied to SARS-CoV2, the concept of original antigenic sin “is new” but Dr. Rost said that it might help differentiate neuroPASC from acute neurologic symptoms of COVID-19, which include stroke. She indicated that the work performed by Dr. Spatola and others might eventually explain the pathology while leading to treatment strategies. She cautioned that the concepts explored in this study “need to be further developed” through larger sample sizes and the exploration of other variables that support the hypothesis.

Dr. Spatola and Dr. Rost report no potential conflicts of interest.

BOSTON – The neurologic symptoms of long COVID appear to be explained by a phenomenon known as antigenic imprinting, which involves a misdirected immune response to the SARS-CoV2 virus, according to a collaborative study presented at the 2023 annual meeting of the American Academy of Neurology.

Already documented in several other viral infections, such as influenza and human immunodeficiency virus, antigenic imprinting results in production of antibodies to previously encountered viral infections rather than to the immediate threat, according to Marianna Spatola, MD, PhD, a research fellow at the Ragon Institute, Harvard University, Cambridge, Mass.
 

Original antigenic sin

In the case of persistent neurologic symptoms after COVID, a condition known as neuroPASC (neurological postacute sequelae of SARS-CoV2 infection), antibodies produced for previously encountered coronaviruses rather than for SARS-CoV2 might explain most or all cases, according to the data Dr. Spatola presented.

The evidence for this explanation was drawn from a study of 112 patients evaluated months after an acute episode of COVID-19. Of these, 18 patients had persistent neurologic dysfunction. When compared with the 94 whose infection resolved without sequelae, the patients with prolonged neurologic impairments had relatively low systemic antibody response to SARS-CoV2. However, they showed relatively high antibody responses against other coronaviruses.

This is a pattern consistent with antigenic imprinting, a concept first described more than 60 years ago as original antigenic sin. When the immune system becomes imprinted with an antigen from the first encountered virus from a family of pathogens, it governs all subsequent antibody responses, according to several published studies that have described and evaluated this concept.
 

Additional evidence

In Dr. Spatola’s study, other differences, particularly in regard to the cerebrospinal fluid (CSF), further supported the role of antigenic imprinting as a cause of neuroPASC. For one, those with elevated immune responses to other common coronaviruses rather than SARS-CoV2 in the CSF relative to the periphery were more likely to have a bad outcome in regard to neurologic symptoms.

Moreover, the CSF in neuroPASC patients “was characterized by increased IgG1 and absence of IgM, suggesting compartmentalized humoral responses within the CSF through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier rather than through intrathecal synthesis,” Dr. Spatola reported.

In the case of COVID-19, the propensity for antigenic imprinting is not difficult to understand.

“The common cold coronaviruses are pretty similar to SARS-CoV2, but they are not exactly the same,” Dr. Spatola said. Her work and studies by others suggest that when antigenic imprinting occurs, “it prevents full maturation of the antibody response.”

NeuroPASC is one of many manifestations of long COVID, but Dr. Spatola pointed out that the immune response in the CSF is unique and the causes of prolonged neurologic impairment after COVID-19 are likely to involve different mechanisms than other long-COVID symptoms.

“Antibodies in the brain are functionally different,” said Dr. Spatola, noting for example that antibody-directed defenses against viral threats show a greater relative reliance on phagocytosis. This might become important in the development of therapeutics for neurologic symptoms of long COVID.
 

A different phenomenon

The manifestations of neuroPASC are heterogeneous and can include confusion, cognitive dysfunction, headache, encephalitis, and other impairments. Neurologic symptoms occur during acute SARS-CoV2 infections, but neuroPASC appears to be a different phenomenon. These symptoms, which develop after the initial respiratory disease has resolved, were attributed by Dr. Spatola to persistent inflammation that is not necessarily directly related to ongoing infection.

“The reason why some patients develop neuroPASC is unknown, but I think the evidence has pointed to a role for the immune system rather than the virus itself,” Dr. Spatola said.

Currently, neuroPASC is a clinical diagnosis but Dr. Spatola and her coinvestigators are conducting research to identify biomarkers. A viable diagnostic test is not expected imminently. They have identified 150 different features with potential relevance to neuroPASC.

In their comparison of those who did relative to those who did not develop neuroPASC, the initial studies were undertaken 2-4 months after the acute COVID-19 symptoms had resolved. The patients with neuroPASC and those without neurologic sequelae have now been followed for 6-8 months, which Dr. Spatola said was too short to draw firm conclusions about outcomes.
 

An evolving concept

Despite the small sample size of this study, these are “very interesting data” for considering the pathogenesis of neuroPASC, which is “a concept that is still evolving,” according to Natalia S. Rost, MD, chief of the stroke division, department of neurology, Massachusetts General Hospital, Boston.

Applied to SARS-CoV2, the concept of original antigenic sin “is new” but Dr. Rost said that it might help differentiate neuroPASC from acute neurologic symptoms of COVID-19, which include stroke. She indicated that the work performed by Dr. Spatola and others might eventually explain the pathology while leading to treatment strategies. She cautioned that the concepts explored in this study “need to be further developed” through larger sample sizes and the exploration of other variables that support the hypothesis.

Dr. Spatola and Dr. Rost report no potential conflicts of interest.

In a phase 2 clinical trial of a potential treatment for fatigue associated with long COVID-19, people who received the medicine reported positive results over those receiving a placebo.

The study was conducted by researchers at the University of Oxford, England, and published in eClinical Medicine.

It was one of the first randomized double-blind placebo controlled trial for a possible treatment for long COVID, according to a press release from the university. 

“People living with long COVID in the trial who received AXA1125 had a significant improvement in fatigue compared to those who received a placebo,” the university reported.

Forty-one people participated. They had fatigue for 18 months beforehand. All completed the study, and none reported serious side effects.

AXA1125 was developed by U.S. pharmaceutical company Axcella Therapeutics.

“Potential causes [of long COVID fatigue] include reduced mitochondrial function and cellular bioenergetics,” the researchers reported.

“AXA1125 was tested in long COVID fatigue as previous data from Axcella showed effects on cellular energetics and inflammation. Emerging data on long COVID suggests that the virus targets the mitochondrial, which are essential to normal energy generation and control of inflammation,” the university noted in its press release. “AXA1125 may improve energy generation and reduce the amount of inflammation in the body.”

The study’s authors wrote that AXA1125 was tied to a “significant reduction in 28-day Chalder Fatigue Questionnaire score relative to placebo.” They said participants who reported less fatigue also had better mitochondrial health and walked farther in a 6-minute test.
 

A version of this article first appeared on WebMD.com.

In a phase 2 clinical trial of a potential treatment for fatigue associated with long COVID-19, people who received the medicine reported positive results over those receiving a placebo.

The study was conducted by researchers at the University of Oxford, England, and published in eClinical Medicine.

It was one of the first randomized double-blind placebo controlled trial for a possible treatment for long COVID, according to a press release from the university. 

“People living with long COVID in the trial who received AXA1125 had a significant improvement in fatigue compared to those who received a placebo,” the university reported.

Forty-one people participated. They had fatigue for 18 months beforehand. All completed the study, and none reported serious side effects.

AXA1125 was developed by U.S. pharmaceutical company Axcella Therapeutics.

“Potential causes [of long COVID fatigue] include reduced mitochondrial function and cellular bioenergetics,” the researchers reported.

“AXA1125 was tested in long COVID fatigue as previous data from Axcella showed effects on cellular energetics and inflammation. Emerging data on long COVID suggests that the virus targets the mitochondrial, which are essential to normal energy generation and control of inflammation,” the university noted in its press release. “AXA1125 may improve energy generation and reduce the amount of inflammation in the body.”

The study’s authors wrote that AXA1125 was tied to a “significant reduction in 28-day Chalder Fatigue Questionnaire score relative to placebo.” They said participants who reported less fatigue also had better mitochondrial health and walked farther in a 6-minute test.
 

A version of this article first appeared on WebMD.com.

In a phase 2 clinical trial of a potential treatment for fatigue associated with long COVID-19, people who received the medicine reported positive results over those receiving a placebo.

The study was conducted by researchers at the University of Oxford, England, and published in eClinical Medicine.

It was one of the first randomized double-blind placebo controlled trial for a possible treatment for long COVID, according to a press release from the university. 

“People living with long COVID in the trial who received AXA1125 had a significant improvement in fatigue compared to those who received a placebo,” the university reported.

Forty-one people participated. They had fatigue for 18 months beforehand. All completed the study, and none reported serious side effects.

AXA1125 was developed by U.S. pharmaceutical company Axcella Therapeutics.

“Potential causes [of long COVID fatigue] include reduced mitochondrial function and cellular bioenergetics,” the researchers reported.

“AXA1125 was tested in long COVID fatigue as previous data from Axcella showed effects on cellular energetics and inflammation. Emerging data on long COVID suggests that the virus targets the mitochondrial, which are essential to normal energy generation and control of inflammation,” the university noted in its press release. “AXA1125 may improve energy generation and reduce the amount of inflammation in the body.”

The study’s authors wrote that AXA1125 was tied to a “significant reduction in 28-day Chalder Fatigue Questionnaire score relative to placebo.” They said participants who reported less fatigue also had better mitochondrial health and walked farther in a 6-minute test.
 

A version of this article first appeared on WebMD.com.

COVID can more than triple the chance of being diagnosed with type 2 diabetes within a year of being infected, according to a new Canadian study.

Men who had even a mild case of COVID were significantly more likely than were noninfected men to be diagnosed with type 2 diabetes. Women didn’t have an increased risk unless they were severely ill.

Both men and women who had severe cases were at the highest risk. People who were hospitalized for COVID treatment had more than a doubled risk of being diagnosed with type 2 diabetes, and those who were admitted to intensive care units had more than a tripled risk.

“This is definitely a concern in terms of long-term outcomes,” researcher and University of British Columbia professor Naveed Z. Janjua, PhD, told The New York Times. “With a respiratory infection, you usually think, ‘Seven or eight days and I’m done with it, that’s it.’ [But] here we’re seeing lingering effects that are lifelong.”

The study was published in JAMA Network Open. Researchers analyzed health data from 2020 and 2021 for 629,935 people, 20% of whom were diagnosed with COVID during that time. Most people in the study had not been vaccinated because vaccines were not widely available then. The health information came from a registry maintained by public health officials in British Columbia. The follow-up period was 257 days.

The authors cautioned that their findings could not say that COVID causes type 2 diabetes; rather, in a commentary published along with the study, Pamela B. Davis, MD, PhD, said the link makes sense because COVID is known to impact the pancreas.

“Such a stress may move a patient from a prediabetic state into diabetes,” wrote Dr. Davis, former dean of Case Western Reserve University, Cleveland, where she is now a professor.

The researchers estimated that the increased pattern of diagnoses of diabetes following COVID infection could increase the rate of the disease occurring in the general population by 3%-5% overall.
 

A version of this article first appeared on WebMD.com.

COVID can more than triple the chance of being diagnosed with type 2 diabetes within a year of being infected, according to a new Canadian study.

Men who had even a mild case of COVID were significantly more likely than were noninfected men to be diagnosed with type 2 diabetes. Women didn’t have an increased risk unless they were severely ill.

Both men and women who had severe cases were at the highest risk. People who were hospitalized for COVID treatment had more than a doubled risk of being diagnosed with type 2 diabetes, and those who were admitted to intensive care units had more than a tripled risk.

“This is definitely a concern in terms of long-term outcomes,” researcher and University of British Columbia professor Naveed Z. Janjua, PhD, told The New York Times. “With a respiratory infection, you usually think, ‘Seven or eight days and I’m done with it, that’s it.’ [But] here we’re seeing lingering effects that are lifelong.”

The study was published in JAMA Network Open. Researchers analyzed health data from 2020 and 2021 for 629,935 people, 20% of whom were diagnosed with COVID during that time. Most people in the study had not been vaccinated because vaccines were not widely available then. The health information came from a registry maintained by public health officials in British Columbia. The follow-up period was 257 days.

The authors cautioned that their findings could not say that COVID causes type 2 diabetes; rather, in a commentary published along with the study, Pamela B. Davis, MD, PhD, said the link makes sense because COVID is known to impact the pancreas.

“Such a stress may move a patient from a prediabetic state into diabetes,” wrote Dr. Davis, former dean of Case Western Reserve University, Cleveland, where she is now a professor.

The researchers estimated that the increased pattern of diagnoses of diabetes following COVID infection could increase the rate of the disease occurring in the general population by 3%-5% overall.
 

A version of this article first appeared on WebMD.com.

COVID can more than triple the chance of being diagnosed with type 2 diabetes within a year of being infected, according to a new Canadian study.

Men who had even a mild case of COVID were significantly more likely than were noninfected men to be diagnosed with type 2 diabetes. Women didn’t have an increased risk unless they were severely ill.

Both men and women who had severe cases were at the highest risk. People who were hospitalized for COVID treatment had more than a doubled risk of being diagnosed with type 2 diabetes, and those who were admitted to intensive care units had more than a tripled risk.

“This is definitely a concern in terms of long-term outcomes,” researcher and University of British Columbia professor Naveed Z. Janjua, PhD, told The New York Times. “With a respiratory infection, you usually think, ‘Seven or eight days and I’m done with it, that’s it.’ [But] here we’re seeing lingering effects that are lifelong.”

The study was published in JAMA Network Open. Researchers analyzed health data from 2020 and 2021 for 629,935 people, 20% of whom were diagnosed with COVID during that time. Most people in the study had not been vaccinated because vaccines were not widely available then. The health information came from a registry maintained by public health officials in British Columbia. The follow-up period was 257 days.

The authors cautioned that their findings could not say that COVID causes type 2 diabetes; rather, in a commentary published along with the study, Pamela B. Davis, MD, PhD, said the link makes sense because COVID is known to impact the pancreas.

“Such a stress may move a patient from a prediabetic state into diabetes,” wrote Dr. Davis, former dean of Case Western Reserve University, Cleveland, where she is now a professor.

The researchers estimated that the increased pattern of diagnoses of diabetes following COVID infection could increase the rate of the disease occurring in the general population by 3%-5% overall.
 

A version of this article first appeared on WebMD.com.

The Centers for Disease Control and Prevention has endorsed a plan to “allow” people over age 65 and those who are immunocompromised to get a second dose of the COVID-19 bivalent booster.

This backs the Food and Drug Administration’s authorization April 18 of the additional shot.

“Following FDA regulatory action, CDC has taken steps to simplify COVID-19 vaccine recommendations and allow more flexibility for people at higher risk who want the option of added protection from additional COVID-19 vaccine doses,” the CDC said in a statement.

The agency is following the recommendations made by its Advisory Committee on Immunization Practices (ACIP). While there was no vote, the group reaffirmed its commitment to boosters overall, proposing that all Americans over age 6 who have not had a bivalent mRNA COVID-19 booster vaccine go ahead and get one.

But most others who’ve already had the bivalent shot – which targets the original COVID strain and the two Omicron variants BA.4 and BA.5 – should wait until the fall to get whatever updated vaccine is available.

The panel did carve out exceptions for people over age 65 and those who are immunocompromised because they are at higher risk for severe COVID-19 complications, Evelyn Twentyman, MD, MPH, the lead official in the CDC’s COVID-19 Vaccine Policy Unit, said during the meeting.

People over 65 can now choose to get a second bivalent mRNA booster shot as long as it has been at least 4 months since the last one, she said, and people who are immunocompromised also should have the flexibility to receive one or more additional bivalent boosters at least 2 months after an initial dose.

Regardless of whether someone is unvaccinated, and regardless of how many single-strain COVID vaccines an individual has previously received, they should get a mRNA bivalent shot, Dr. Twentyman said.

If an individual has already received a bivalent mRNA booster – made by either Pfizer/BioNTech or Moderna – “your vaccination is complete,” she said. “No doses indicated at this time, come back and see us in autumn of 2023.”

The CDC is trying to encourage more people to get the updated COVID shot, as just 17% of Americans of any age have received a bivalent booster and only 43% of those age 65 and over.

The CDC followed the FDA’s lead in its statement, phasing out the original single-strain COVID vaccine, saying it will no longer be recommended for use in the United States.
 

‘Unnecessary drama’ over children’s recs

The CDC panel mostly followed the FDA’s guidance on who should get a booster, but many ACIP members expressed consternation and confusion about what was being recommended for children.

For children aged 6 months to 4 years, the CDC will offer tables to help physicians determine how many bivalent doses to give, depending on the child’s vaccination history.

All children those ages should get at least two vaccine doses, one of which is bivalent, Dr. Twentyman said. For children in that age group who have already received a monovalent series and a bivalent dose, “their vaccination is complete,” she said.

For 5-year-olds, the recommendations will be similar if they received a Pfizer monovalent series, but the shot regimen will have to be customized if they had previously received a Moderna shot, because of differences in the dosages.

ACIP member Sarah S. Long, MD, professor of pediatrics, Drexel University, Philadelphia, said that it was unclear why a set age couldn’t be established for COVID-19 vaccination as it had been for other immunizations.

“We picked 60 months for most immunizations in children,” Dr. Long said. “Immunologically there is not a difference between a 4-, a 5- and a 6-year-old.

“There isn’t a reason to have all this unnecessary drama around those ages,” she said, adding that having the different ages would make it harder for pediatricians to appropriately stock vaccines.

Dr. Twentyman said that the CDC would be providing more detailed guidance on its COVID-19 website soon and would be holding a call with health care professionals to discuss the updated recommendations on May 11.
 

New vaccine by fall

CDC and ACIP members both said they hoped to have an even simpler vaccine schedule by the fall, when it is anticipated that the FDA may have authorized a new, updated bivalent vaccine that targets other COVID variants.

“We all recognize this is a work in progress,” said ACIP Chair Grace M. Lee, MD, MPH, acknowledging that there is continued confusion over COVID-19 vaccination.

“The goal really is to try to simplify things over time to be able to help communicate with our provider community, and our patients and families what vaccine is right for them, when do they need it, and how often should they get it,” said Dr. Lee, professor of pediatrics, Stanford (Calif.) University.
 

A version of this article originally appeared on Medscape.com .

The Centers for Disease Control and Prevention has endorsed a plan to “allow” people over age 65 and those who are immunocompromised to get a second dose of the COVID-19 bivalent booster.

This backs the Food and Drug Administration’s authorization April 18 of the additional shot.

“Following FDA regulatory action, CDC has taken steps to simplify COVID-19 vaccine recommendations and allow more flexibility for people at higher risk who want the option of added protection from additional COVID-19 vaccine doses,” the CDC said in a statement.

The agency is following the recommendations made by its Advisory Committee on Immunization Practices (ACIP). While there was no vote, the group reaffirmed its commitment to boosters overall, proposing that all Americans over age 6 who have not had a bivalent mRNA COVID-19 booster vaccine go ahead and get one.

But most others who’ve already had the bivalent shot – which targets the original COVID strain and the two Omicron variants BA.4 and BA.5 – should wait until the fall to get whatever updated vaccine is available.

The panel did carve out exceptions for people over age 65 and those who are immunocompromised because they are at higher risk for severe COVID-19 complications, Evelyn Twentyman, MD, MPH, the lead official in the CDC’s COVID-19 Vaccine Policy Unit, said during the meeting.

People over 65 can now choose to get a second bivalent mRNA booster shot as long as it has been at least 4 months since the last one, she said, and people who are immunocompromised also should have the flexibility to receive one or more additional bivalent boosters at least 2 months after an initial dose.

Regardless of whether someone is unvaccinated, and regardless of how many single-strain COVID vaccines an individual has previously received, they should get a mRNA bivalent shot, Dr. Twentyman said.

If an individual has already received a bivalent mRNA booster – made by either Pfizer/BioNTech or Moderna – “your vaccination is complete,” she said. “No doses indicated at this time, come back and see us in autumn of 2023.”

The CDC is trying to encourage more people to get the updated COVID shot, as just 17% of Americans of any age have received a bivalent booster and only 43% of those age 65 and over.

The CDC followed the FDA’s lead in its statement, phasing out the original single-strain COVID vaccine, saying it will no longer be recommended for use in the United States.
 

‘Unnecessary drama’ over children’s recs

The CDC panel mostly followed the FDA’s guidance on who should get a booster, but many ACIP members expressed consternation and confusion about what was being recommended for children.

For children aged 6 months to 4 years, the CDC will offer tables to help physicians determine how many bivalent doses to give, depending on the child’s vaccination history.

All children those ages should get at least two vaccine doses, one of which is bivalent, Dr. Twentyman said. For children in that age group who have already received a monovalent series and a bivalent dose, “their vaccination is complete,” she said.

For 5-year-olds, the recommendations will be similar if they received a Pfizer monovalent series, but the shot regimen will have to be customized if they had previously received a Moderna shot, because of differences in the dosages.

ACIP member Sarah S. Long, MD, professor of pediatrics, Drexel University, Philadelphia, said that it was unclear why a set age couldn’t be established for COVID-19 vaccination as it had been for other immunizations.

“We picked 60 months for most immunizations in children,” Dr. Long said. “Immunologically there is not a difference between a 4-, a 5- and a 6-year-old.

“There isn’t a reason to have all this unnecessary drama around those ages,” she said, adding that having the different ages would make it harder for pediatricians to appropriately stock vaccines.

Dr. Twentyman said that the CDC would be providing more detailed guidance on its COVID-19 website soon and would be holding a call with health care professionals to discuss the updated recommendations on May 11.
 

New vaccine by fall

CDC and ACIP members both said they hoped to have an even simpler vaccine schedule by the fall, when it is anticipated that the FDA may have authorized a new, updated bivalent vaccine that targets other COVID variants.

“We all recognize this is a work in progress,” said ACIP Chair Grace M. Lee, MD, MPH, acknowledging that there is continued confusion over COVID-19 vaccination.

“The goal really is to try to simplify things over time to be able to help communicate with our provider community, and our patients and families what vaccine is right for them, when do they need it, and how often should they get it,” said Dr. Lee, professor of pediatrics, Stanford (Calif.) University.
 

A version of this article originally appeared on Medscape.com .

The Centers for Disease Control and Prevention has endorsed a plan to “allow” people over age 65 and those who are immunocompromised to get a second dose of the COVID-19 bivalent booster.

This backs the Food and Drug Administration’s authorization April 18 of the additional shot.

“Following FDA regulatory action, CDC has taken steps to simplify COVID-19 vaccine recommendations and allow more flexibility for people at higher risk who want the option of added protection from additional COVID-19 vaccine doses,” the CDC said in a statement.

The agency is following the recommendations made by its Advisory Committee on Immunization Practices (ACIP). While there was no vote, the group reaffirmed its commitment to boosters overall, proposing that all Americans over age 6 who have not had a bivalent mRNA COVID-19 booster vaccine go ahead and get one.

But most others who’ve already had the bivalent shot – which targets the original COVID strain and the two Omicron variants BA.4 and BA.5 – should wait until the fall to get whatever updated vaccine is available.

The panel did carve out exceptions for people over age 65 and those who are immunocompromised because they are at higher risk for severe COVID-19 complications, Evelyn Twentyman, MD, MPH, the lead official in the CDC’s COVID-19 Vaccine Policy Unit, said during the meeting.

People over 65 can now choose to get a second bivalent mRNA booster shot as long as it has been at least 4 months since the last one, she said, and people who are immunocompromised also should have the flexibility to receive one or more additional bivalent boosters at least 2 months after an initial dose.

Regardless of whether someone is unvaccinated, and regardless of how many single-strain COVID vaccines an individual has previously received, they should get a mRNA bivalent shot, Dr. Twentyman said.

If an individual has already received a bivalent mRNA booster – made by either Pfizer/BioNTech or Moderna – “your vaccination is complete,” she said. “No doses indicated at this time, come back and see us in autumn of 2023.”

The CDC is trying to encourage more people to get the updated COVID shot, as just 17% of Americans of any age have received a bivalent booster and only 43% of those age 65 and over.

The CDC followed the FDA’s lead in its statement, phasing out the original single-strain COVID vaccine, saying it will no longer be recommended for use in the United States.
 

‘Unnecessary drama’ over children’s recs

The CDC panel mostly followed the FDA’s guidance on who should get a booster, but many ACIP members expressed consternation and confusion about what was being recommended for children.

For children aged 6 months to 4 years, the CDC will offer tables to help physicians determine how many bivalent doses to give, depending on the child’s vaccination history.

All children those ages should get at least two vaccine doses, one of which is bivalent, Dr. Twentyman said. For children in that age group who have already received a monovalent series and a bivalent dose, “their vaccination is complete,” she said.

For 5-year-olds, the recommendations will be similar if they received a Pfizer monovalent series, but the shot regimen will have to be customized if they had previously received a Moderna shot, because of differences in the dosages.

ACIP member Sarah S. Long, MD, professor of pediatrics, Drexel University, Philadelphia, said that it was unclear why a set age couldn’t be established for COVID-19 vaccination as it had been for other immunizations.

“We picked 60 months for most immunizations in children,” Dr. Long said. “Immunologically there is not a difference between a 4-, a 5- and a 6-year-old.

“There isn’t a reason to have all this unnecessary drama around those ages,” she said, adding that having the different ages would make it harder for pediatricians to appropriately stock vaccines.

Dr. Twentyman said that the CDC would be providing more detailed guidance on its COVID-19 website soon and would be holding a call with health care professionals to discuss the updated recommendations on May 11.
 

New vaccine by fall

CDC and ACIP members both said they hoped to have an even simpler vaccine schedule by the fall, when it is anticipated that the FDA may have authorized a new, updated bivalent vaccine that targets other COVID variants.

“We all recognize this is a work in progress,” said ACIP Chair Grace M. Lee, MD, MPH, acknowledging that there is continued confusion over COVID-19 vaccination.

“The goal really is to try to simplify things over time to be able to help communicate with our provider community, and our patients and families what vaccine is right for them, when do they need it, and how often should they get it,” said Dr. Lee, professor of pediatrics, Stanford (Calif.) University.
 

A version of this article originally appeared on Medscape.com .

Poor-quality sleep and irregular sleep could be important drivers of breathlessness in patients who were previously hospitalized for COVID-19, according to data from the U.K.’s CircCOVID study.

The researchers, led by John Blaikley, MRCP, PhD, respiratory physician and clinical scientist from the University of Manchester (England), found that sleep disturbance is a common problem after hospital admission for COVID-19 and may last for at least 1 year.

The study also showed that sleep disturbance after COVID hospitalization was associated with dyspnea and lower lung function. Further in-depth analysis revealed that the effects of sleep disturbance on dyspnea were partially mediated through both anxiety and muscle weakness; however, “this does not fully explain the association, suggesting other pathways are involved,” said Dr. Blaikley.

The study was jointly conducted by researchers from the University of Leicester (England), as well as 20 other U.K. institutes and the University of Helsinki. It was presented at the European Congress of Clinical Microbiology & Infectious Diseases and was simultaneously published in The Lancet Respiratory Medicine.

“Sleep disturbance is a common problem after hospitalization for COVID-19 and is associated with several symptoms in the post-COVID syndrome,” said Dr. Blaikley. “Clinicians should be aware of this association in their post-COVID syndrome clinics.”

He added that further work needs to be done to define the mechanism and to see whether the links are causal. “However, if they are, then treating sleep disturbance could have beneficial effects beyond improving sleep quality,” he said in an interview.

A large study recently showed that 4 in 10 people with post-COVID syndrome had moderate to severe sleep problems. Black people were at least three times more likely than White people to experience sleep problems. A total of 59% of all participants with long COVID reported having normal sleep or mild sleep disturbances, and 41% reported having moderate to severe sleep disturbances.

Unlike prior studies that evaluated sleep quality after COVID-19, which used either objective or subjective measures of sleep disturbance, the current study used both. “Using both measures revealed previously poorly described associations between sleep disturbance, breathlessness, reduced lung function, anxiety, and muscle weakness,” Dr. Blaikley pointed out.

Subjective and objective measures of sleep

The multicenter CircCOVID cohort study aimed to shed light on the prevalence and nature of sleep disturbance after patients are discharged from hospital for COVID-19 and to assess whether this was associated with dyspnea.

The study recruited a total of 2,320 participants who were part of a larger parent PHOSP-COVID study. After attending an early follow-up visit (at a median of 5 months after discharge from 83 U.K. hospitals for COVID-19), 638 participants provided data for analysis as measured by the Pittsburgh Sleep Quality Index (a subjective measure of sleep quality); 729 participants provided data for analysis as measured by actigraphy (an objective, wrist-worn, device-based measure of sleep quality) at a median of 7 months.

Breathlessness, the primary outcome, was assessed using the Dyspnea-12 validated questionnaire.

Actigraphy measurements were compared with an age-matched, sex-matched, body mass index (BMI)–matched, and time from discharge–matched cohort from the UK Biobank (a prepandemic comparator longitudinal cohort of 502,540 individuals, one-fifth of whom wore actigraphy devices). Sleep regularity was found to be 19% less in previously hospitalized patients with post-COVID syndrome, compared with matched controls who had been hospitalized for other reasons.

This “revealed that the actigraphy changes may be, in part, due to COVID-19 rather than hospitalization alone,” said Dr. Blaikley.

Data were collected at two time points after hospital discharge: 2-7 months (early), and 10-14 months (late). At the early time point, participants were clinically assessed with respect to anxiety, muscle function, and dyspnea, and lung function.

After discharge from hospital, the majority (62%) of post–COVID-19 participants reported poor sleep quality on the Pittsburgh Sleep Quality Index questionnaire. A “comparable” proportion (53%) felt that their quality of sleep had deteriorated following hospital discharge according to the numerical rating scale (subjective measure).

Also, sleep disturbance was found likely to persist for at least 12 months, since subjective sleep quality hardly changed between the early and late time points after hospital discharge.

Both subjective metrics (sleep quality and sleep quality deterioration after hospital discharge) and objective, device-based metrics (sleep regularity) were found to be associated with dyspnea and reduced lung function in patients with post-COVID syndrome.

“One of the striking findings in our study is the consistency with breathlessness and reduced lung function across different methods used to evaluate sleep,” highlighted Dr. Blaikley.

“The other striking finding was that participants following COVID-19 hospitalization actually slept longer [65 min; 95% confidence interval, 59-71 min] than participants hospitalized for non-COVID; however, their bedtimes were irregular, and it was this irregularity that was associated with breathlessness,” he added.

In comparison with nonhospitalized controls, also from the UK Biobank, study participants with lower sleep regularity had higher Dyspnea-12 scores (unadjusted effect estimate, 4.38; 95%: CI, 2.10-6.65). Those with poor sleep quality overall also had higher Dyspnea-12 scores (unadjusted effect estimate, 3.94; 95% CI, 2.78-5.10), and those who reported sleep quality deterioration had higher Dyspnea-12 scores (unadjusted effect estimate, 3,00; 95% CI, 1.82-4.28).

In comparison with hospitalized controls, CircCOVID participants had lower sleep regularity index (–19%; 95% CI, –20 to –16) and lower sleep efficiency (3.83 percentage points; 95% CI, 3.40-4.26).

Sleep disturbance after COVID hospitalization was also associated with lower lung function, from a 7% to a 14% reduction in predicted forced vital capacity, depending on which sleep measure used.

In an analysis of mediating factors active in the relationship between sleep disturbance and dyspnea/decreased lung function, the researchers found that reduced muscle function and anxiety, which are both recognized causes of dyspnea, could partially contribute to the association.

Regarding anxiety, and depending on the sleep metric, anxiety mediated 18%-39% of the effect of sleep disturbance on dyspnea, while muscle weakness mediated 27%-41% of this effect, reported Dr. Blaikley. Those with poor sleep quality were more likely to have mild, moderate, or severe anxiety, compared with participants who reported good-quality sleep.

A similar association was observed between anxiety and sleep quality deterioration.

“Two key questions are raised by our study: Do sleep interventions have a beneficial effect in post–COVID-19 syndrome, and are the associations causal?” asked Dr. Blaikley. “We hope to do a sleep intervention trial to answer these questions to explore if this is an effective treatment for post–COVID-19 syndrome.”

‘Underlying mechanisms remain unclear’

Amitava Banerjee, MD, professor of clinical data science and honorary consultant cardiologist, Institute of Health Informatics, UCL, London, welcomed the study but noted that it did not include nonhospitalized post-COVID patients.

“The majority of people with long COVID were not hospitalized for COVID, so the results may not be generalizable to this larger group,” she said in an interview. “Good-quality sleep is important for health and reduces risk of chronic diseases; quality of sleep is therefore likely to be important for those with long COVID in reducing their risk of chronic disease, but the role of sleep in the mechanism of long COVID needs further research.”

In a commentary also published in The Lancet Respiratory Medicine, W. Cameron McGuire, MD, pulmonary and critical care specialist from San Diego, California, and colleagues wrote: “These findings suggest that sleep disturbance, dyspnea, and anxiety are common after COVID-19 and are associated with one another, although the underlying mechanisms remain unclear.”

The commentators “applauded” the work overall but noted that the findings represent correlation rather than causation. “It is unclear whether sleep disturbance is causing anxiety or whether anxiety is contributing to poor sleep. ... For the sleep disturbances, increased BMI in the cohort reporting poor sleep, compared with those reporting good sleep might suggest underlying obstructive sleep apnea,” they wrote.

Dr. McGuire and colleagues added that many questions remain for researchers and clinicians, including “whether anxiety and dyspnoea are contributing to a low arousal threshold [disrupting sleep] ... whether the observed abnormalities (e.g., in dyspnea score) are clinically significant,” and “whether therapies such as glucocorticoids, anticoagulants, or previous vaccinations mitigate the observed abnormalities during COVID-19 recovery.”

Dr. Blaikley has received support to his institute from an MRC Transition Fellowship, Asthma + Lung UK, NIHR Manchester BRC, and UKRI; grants to his institution from the Small Business Research Initiative Home Spirometer and the National Institute of Academic Anaesthesia; and support from TEVA and Therakos for attending meetings. He is a committee member of the Royal Society of Medicine. A coauthor received funding from the National Institutes of Health and income for medical education from Zoll, Livanova, Jazz, and Eli Lilly. Dr. Banerjee is the chief investigator of STIMULATE-ICP (an NIHR-funded study) and has received research funding from AstraZeneca.

A version of this article first appeared on Medscape.com.

Poor-quality sleep and irregular sleep could be important drivers of breathlessness in patients who were previously hospitalized for COVID-19, according to data from the U.K.’s CircCOVID study.

The researchers, led by John Blaikley, MRCP, PhD, respiratory physician and clinical scientist from the University of Manchester (England), found that sleep disturbance is a common problem after hospital admission for COVID-19 and may last for at least 1 year.

The study also showed that sleep disturbance after COVID hospitalization was associated with dyspnea and lower lung function. Further in-depth analysis revealed that the effects of sleep disturbance on dyspnea were partially mediated through both anxiety and muscle weakness; however, “this does not fully explain the association, suggesting other pathways are involved,” said Dr. Blaikley.

The study was jointly conducted by researchers from the University of Leicester (England), as well as 20 other U.K. institutes and the University of Helsinki. It was presented at the European Congress of Clinical Microbiology & Infectious Diseases and was simultaneously published in The Lancet Respiratory Medicine.

“Sleep disturbance is a common problem after hospitalization for COVID-19 and is associated with several symptoms in the post-COVID syndrome,” said Dr. Blaikley. “Clinicians should be aware of this association in their post-COVID syndrome clinics.”

He added that further work needs to be done to define the mechanism and to see whether the links are causal. “However, if they are, then treating sleep disturbance could have beneficial effects beyond improving sleep quality,” he said in an interview.

A large study recently showed that 4 in 10 people with post-COVID syndrome had moderate to severe sleep problems. Black people were at least three times more likely than White people to experience sleep problems. A total of 59% of all participants with long COVID reported having normal sleep or mild sleep disturbances, and 41% reported having moderate to severe sleep disturbances.

Unlike prior studies that evaluated sleep quality after COVID-19, which used either objective or subjective measures of sleep disturbance, the current study used both. “Using both measures revealed previously poorly described associations between sleep disturbance, breathlessness, reduced lung function, anxiety, and muscle weakness,” Dr. Blaikley pointed out.

Subjective and objective measures of sleep

The multicenter CircCOVID cohort study aimed to shed light on the prevalence and nature of sleep disturbance after patients are discharged from hospital for COVID-19 and to assess whether this was associated with dyspnea.

The study recruited a total of 2,320 participants who were part of a larger parent PHOSP-COVID study. After attending an early follow-up visit (at a median of 5 months after discharge from 83 U.K. hospitals for COVID-19), 638 participants provided data for analysis as measured by the Pittsburgh Sleep Quality Index (a subjective measure of sleep quality); 729 participants provided data for analysis as measured by actigraphy (an objective, wrist-worn, device-based measure of sleep quality) at a median of 7 months.

Breathlessness, the primary outcome, was assessed using the Dyspnea-12 validated questionnaire.

Actigraphy measurements were compared with an age-matched, sex-matched, body mass index (BMI)–matched, and time from discharge–matched cohort from the UK Biobank (a prepandemic comparator longitudinal cohort of 502,540 individuals, one-fifth of whom wore actigraphy devices). Sleep regularity was found to be 19% less in previously hospitalized patients with post-COVID syndrome, compared with matched controls who had been hospitalized for other reasons.

This “revealed that the actigraphy changes may be, in part, due to COVID-19 rather than hospitalization alone,” said Dr. Blaikley.

Data were collected at two time points after hospital discharge: 2-7 months (early), and 10-14 months (late). At the early time point, participants were clinically assessed with respect to anxiety, muscle function, and dyspnea, and lung function.

After discharge from hospital, the majority (62%) of post–COVID-19 participants reported poor sleep quality on the Pittsburgh Sleep Quality Index questionnaire. A “comparable” proportion (53%) felt that their quality of sleep had deteriorated following hospital discharge according to the numerical rating scale (subjective measure).

Also, sleep disturbance was found likely to persist for at least 12 months, since subjective sleep quality hardly changed between the early and late time points after hospital discharge.

Both subjective metrics (sleep quality and sleep quality deterioration after hospital discharge) and objective, device-based metrics (sleep regularity) were found to be associated with dyspnea and reduced lung function in patients with post-COVID syndrome.

“One of the striking findings in our study is the consistency with breathlessness and reduced lung function across different methods used to evaluate sleep,” highlighted Dr. Blaikley.

“The other striking finding was that participants following COVID-19 hospitalization actually slept longer [65 min; 95% confidence interval, 59-71 min] than participants hospitalized for non-COVID; however, their bedtimes were irregular, and it was this irregularity that was associated with breathlessness,” he added.

In comparison with nonhospitalized controls, also from the UK Biobank, study participants with lower sleep regularity had higher Dyspnea-12 scores (unadjusted effect estimate, 4.38; 95%: CI, 2.10-6.65). Those with poor sleep quality overall also had higher Dyspnea-12 scores (unadjusted effect estimate, 3.94; 95% CI, 2.78-5.10), and those who reported sleep quality deterioration had higher Dyspnea-12 scores (unadjusted effect estimate, 3,00; 95% CI, 1.82-4.28).

In comparison with hospitalized controls, CircCOVID participants had lower sleep regularity index (–19%; 95% CI, –20 to –16) and lower sleep efficiency (3.83 percentage points; 95% CI, 3.40-4.26).

Sleep disturbance after COVID hospitalization was also associated with lower lung function, from a 7% to a 14% reduction in predicted forced vital capacity, depending on which sleep measure used.

In an analysis of mediating factors active in the relationship between sleep disturbance and dyspnea/decreased lung function, the researchers found that reduced muscle function and anxiety, which are both recognized causes of dyspnea, could partially contribute to the association.

Regarding anxiety, and depending on the sleep metric, anxiety mediated 18%-39% of the effect of sleep disturbance on dyspnea, while muscle weakness mediated 27%-41% of this effect, reported Dr. Blaikley. Those with poor sleep quality were more likely to have mild, moderate, or severe anxiety, compared with participants who reported good-quality sleep.

A similar association was observed between anxiety and sleep quality deterioration.

“Two key questions are raised by our study: Do sleep interventions have a beneficial effect in post–COVID-19 syndrome, and are the associations causal?” asked Dr. Blaikley. “We hope to do a sleep intervention trial to answer these questions to explore if this is an effective treatment for post–COVID-19 syndrome.”

‘Underlying mechanisms remain unclear’

Amitava Banerjee, MD, professor of clinical data science and honorary consultant cardiologist, Institute of Health Informatics, UCL, London, welcomed the study but noted that it did not include nonhospitalized post-COVID patients.

“The majority of people with long COVID were not hospitalized for COVID, so the results may not be generalizable to this larger group,” she said in an interview. “Good-quality sleep is important for health and reduces risk of chronic diseases; quality of sleep is therefore likely to be important for those with long COVID in reducing their risk of chronic disease, but the role of sleep in the mechanism of long COVID needs further research.”

In a commentary also published in The Lancet Respiratory Medicine, W. Cameron McGuire, MD, pulmonary and critical care specialist from San Diego, California, and colleagues wrote: “These findings suggest that sleep disturbance, dyspnea, and anxiety are common after COVID-19 and are associated with one another, although the underlying mechanisms remain unclear.”

The commentators “applauded” the work overall but noted that the findings represent correlation rather than causation. “It is unclear whether sleep disturbance is causing anxiety or whether anxiety is contributing to poor sleep. ... For the sleep disturbances, increased BMI in the cohort reporting poor sleep, compared with those reporting good sleep might suggest underlying obstructive sleep apnea,” they wrote.

Dr. McGuire and colleagues added that many questions remain for researchers and clinicians, including “whether anxiety and dyspnoea are contributing to a low arousal threshold [disrupting sleep] ... whether the observed abnormalities (e.g., in dyspnea score) are clinically significant,” and “whether therapies such as glucocorticoids, anticoagulants, or previous vaccinations mitigate the observed abnormalities during COVID-19 recovery.”

Dr. Blaikley has received support to his institute from an MRC Transition Fellowship, Asthma + Lung UK, NIHR Manchester BRC, and UKRI; grants to his institution from the Small Business Research Initiative Home Spirometer and the National Institute of Academic Anaesthesia; and support from TEVA and Therakos for attending meetings. He is a committee member of the Royal Society of Medicine. A coauthor received funding from the National Institutes of Health and income for medical education from Zoll, Livanova, Jazz, and Eli Lilly. Dr. Banerjee is the chief investigator of STIMULATE-ICP (an NIHR-funded study) and has received research funding from AstraZeneca.

A version of this article first appeared on Medscape.com.

Poor-quality sleep and irregular sleep could be important drivers of breathlessness in patients who were previously hospitalized for COVID-19, according to data from the U.K.’s CircCOVID study.

The researchers, led by John Blaikley, MRCP, PhD, respiratory physician and clinical scientist from the University of Manchester (England), found that sleep disturbance is a common problem after hospital admission for COVID-19 and may last for at least 1 year.

The study also showed that sleep disturbance after COVID hospitalization was associated with dyspnea and lower lung function. Further in-depth analysis revealed that the effects of sleep disturbance on dyspnea were partially mediated through both anxiety and muscle weakness; however, “this does not fully explain the association, suggesting other pathways are involved,” said Dr. Blaikley.

The study was jointly conducted by researchers from the University of Leicester (England), as well as 20 other U.K. institutes and the University of Helsinki. It was presented at the European Congress of Clinical Microbiology & Infectious Diseases and was simultaneously published in The Lancet Respiratory Medicine.

“Sleep disturbance is a common problem after hospitalization for COVID-19 and is associated with several symptoms in the post-COVID syndrome,” said Dr. Blaikley. “Clinicians should be aware of this association in their post-COVID syndrome clinics.”

He added that further work needs to be done to define the mechanism and to see whether the links are causal. “However, if they are, then treating sleep disturbance could have beneficial effects beyond improving sleep quality,” he said in an interview.

A large study recently showed that 4 in 10 people with post-COVID syndrome had moderate to severe sleep problems. Black people were at least three times more likely than White people to experience sleep problems. A total of 59% of all participants with long COVID reported having normal sleep or mild sleep disturbances, and 41% reported having moderate to severe sleep disturbances.

Unlike prior studies that evaluated sleep quality after COVID-19, which used either objective or subjective measures of sleep disturbance, the current study used both. “Using both measures revealed previously poorly described associations between sleep disturbance, breathlessness, reduced lung function, anxiety, and muscle weakness,” Dr. Blaikley pointed out.

Subjective and objective measures of sleep

The multicenter CircCOVID cohort study aimed to shed light on the prevalence and nature of sleep disturbance after patients are discharged from hospital for COVID-19 and to assess whether this was associated with dyspnea.

The study recruited a total of 2,320 participants who were part of a larger parent PHOSP-COVID study. After attending an early follow-up visit (at a median of 5 months after discharge from 83 U.K. hospitals for COVID-19), 638 participants provided data for analysis as measured by the Pittsburgh Sleep Quality Index (a subjective measure of sleep quality); 729 participants provided data for analysis as measured by actigraphy (an objective, wrist-worn, device-based measure of sleep quality) at a median of 7 months.

Breathlessness, the primary outcome, was assessed using the Dyspnea-12 validated questionnaire.

Actigraphy measurements were compared with an age-matched, sex-matched, body mass index (BMI)–matched, and time from discharge–matched cohort from the UK Biobank (a prepandemic comparator longitudinal cohort of 502,540 individuals, one-fifth of whom wore actigraphy devices). Sleep regularity was found to be 19% less in previously hospitalized patients with post-COVID syndrome, compared with matched controls who had been hospitalized for other reasons.

This “revealed that the actigraphy changes may be, in part, due to COVID-19 rather than hospitalization alone,” said Dr. Blaikley.

Data were collected at two time points after hospital discharge: 2-7 months (early), and 10-14 months (late). At the early time point, participants were clinically assessed with respect to anxiety, muscle function, and dyspnea, and lung function.

After discharge from hospital, the majority (62%) of post–COVID-19 participants reported poor sleep quality on the Pittsburgh Sleep Quality Index questionnaire. A “comparable” proportion (53%) felt that their quality of sleep had deteriorated following hospital discharge according to the numerical rating scale (subjective measure).

Also, sleep disturbance was found likely to persist for at least 12 months, since subjective sleep quality hardly changed between the early and late time points after hospital discharge.

Both subjective metrics (sleep quality and sleep quality deterioration after hospital discharge) and objective, device-based metrics (sleep regularity) were found to be associated with dyspnea and reduced lung function in patients with post-COVID syndrome.

“One of the striking findings in our study is the consistency with breathlessness and reduced lung function across different methods used to evaluate sleep,” highlighted Dr. Blaikley.

“The other striking finding was that participants following COVID-19 hospitalization actually slept longer [65 min; 95% confidence interval, 59-71 min] than participants hospitalized for non-COVID; however, their bedtimes were irregular, and it was this irregularity that was associated with breathlessness,” he added.

In comparison with nonhospitalized controls, also from the UK Biobank, study participants with lower sleep regularity had higher Dyspnea-12 scores (unadjusted effect estimate, 4.38; 95%: CI, 2.10-6.65). Those with poor sleep quality overall also had higher Dyspnea-12 scores (unadjusted effect estimate, 3.94; 95% CI, 2.78-5.10), and those who reported sleep quality deterioration had higher Dyspnea-12 scores (unadjusted effect estimate, 3,00; 95% CI, 1.82-4.28).

In comparison with hospitalized controls, CircCOVID participants had lower sleep regularity index (–19%; 95% CI, –20 to –16) and lower sleep efficiency (3.83 percentage points; 95% CI, 3.40-4.26).

Sleep disturbance after COVID hospitalization was also associated with lower lung function, from a 7% to a 14% reduction in predicted forced vital capacity, depending on which sleep measure used.

In an analysis of mediating factors active in the relationship between sleep disturbance and dyspnea/decreased lung function, the researchers found that reduced muscle function and anxiety, which are both recognized causes of dyspnea, could partially contribute to the association.

Regarding anxiety, and depending on the sleep metric, anxiety mediated 18%-39% of the effect of sleep disturbance on dyspnea, while muscle weakness mediated 27%-41% of this effect, reported Dr. Blaikley. Those with poor sleep quality were more likely to have mild, moderate, or severe anxiety, compared with participants who reported good-quality sleep.

A similar association was observed between anxiety and sleep quality deterioration.

“Two key questions are raised by our study: Do sleep interventions have a beneficial effect in post–COVID-19 syndrome, and are the associations causal?” asked Dr. Blaikley. “We hope to do a sleep intervention trial to answer these questions to explore if this is an effective treatment for post–COVID-19 syndrome.”

‘Underlying mechanisms remain unclear’

Amitava Banerjee, MD, professor of clinical data science and honorary consultant cardiologist, Institute of Health Informatics, UCL, London, welcomed the study but noted that it did not include nonhospitalized post-COVID patients.

“The majority of people with long COVID were not hospitalized for COVID, so the results may not be generalizable to this larger group,” she said in an interview. “Good-quality sleep is important for health and reduces risk of chronic diseases; quality of sleep is therefore likely to be important for those with long COVID in reducing their risk of chronic disease, but the role of sleep in the mechanism of long COVID needs further research.”

In a commentary also published in The Lancet Respiratory Medicine, W. Cameron McGuire, MD, pulmonary and critical care specialist from San Diego, California, and colleagues wrote: “These findings suggest that sleep disturbance, dyspnea, and anxiety are common after COVID-19 and are associated with one another, although the underlying mechanisms remain unclear.”

The commentators “applauded” the work overall but noted that the findings represent correlation rather than causation. “It is unclear whether sleep disturbance is causing anxiety or whether anxiety is contributing to poor sleep. ... For the sleep disturbances, increased BMI in the cohort reporting poor sleep, compared with those reporting good sleep might suggest underlying obstructive sleep apnea,” they wrote.

Dr. McGuire and colleagues added that many questions remain for researchers and clinicians, including “whether anxiety and dyspnoea are contributing to a low arousal threshold [disrupting sleep] ... whether the observed abnormalities (e.g., in dyspnea score) are clinically significant,” and “whether therapies such as glucocorticoids, anticoagulants, or previous vaccinations mitigate the observed abnormalities during COVID-19 recovery.”

Dr. Blaikley has received support to his institute from an MRC Transition Fellowship, Asthma + Lung UK, NIHR Manchester BRC, and UKRI; grants to his institution from the Small Business Research Initiative Home Spirometer and the National Institute of Academic Anaesthesia; and support from TEVA and Therakos for attending meetings. He is a committee member of the Royal Society of Medicine. A coauthor received funding from the National Institutes of Health and income for medical education from Zoll, Livanova, Jazz, and Eli Lilly. Dr. Banerjee is the chief investigator of STIMULATE-ICP (an NIHR-funded study) and has received research funding from AstraZeneca.

A version of this article first appeared on Medscape.com.

The new COVID-19 strain known as “Arcturus” has increased in the United States so much that it has been added to the Centers for Disease and Control’s watch list.

Officially labeled XBB.1.16, Arcturus is a subvariant of Omicron that was first seen in India and has been on the World Health Organization’s watchlist since the end of March. The CDC’s most recent update now lists Arcturus as causing 7% of U.S. coronavirus cases, landing it in second place behind its long-predominant Omicron cousin XBB.1.5, which causes 78% of cases.

Arcturus is more transmissible but not more dangerous than recent chart-topping strains, experts say.

“It is causing increasing case counts in certain parts of the world, including India. We’re not seeing high rates of XBB.1.16 yet in the United States, but it may become more prominent in coming weeks,” Mayo Clinic viral disease expert Matthew Binnicker, PhD, told The Seattle Times.

Arcturus has been causing a new symptom in children, Indian medical providers have reported.

“One new feature of cases caused by this variant is that it seems to be causing conjunctivitis, or red and itchy eyes, in young patients,” Dr. Binnicker said. “This is not something that we’ve seen with prior strains of the virus.”

More than 11,000 people in the United States remained hospitalized with COVID at the end of last week, and 1,327 people died of the virus last week, CDC data show. To date, 6.9 million people worldwide have died from COVID, the WHO says. Of those deaths, more than 1.1 million occurred in the U.S.

A version of this article originally appeared on WebMD.com.

The new COVID-19 strain known as “Arcturus” has increased in the United States so much that it has been added to the Centers for Disease and Control’s watch list.

Officially labeled XBB.1.16, Arcturus is a subvariant of Omicron that was first seen in India and has been on the World Health Organization’s watchlist since the end of March. The CDC’s most recent update now lists Arcturus as causing 7% of U.S. coronavirus cases, landing it in second place behind its long-predominant Omicron cousin XBB.1.5, which causes 78% of cases.

Arcturus is more transmissible but not more dangerous than recent chart-topping strains, experts say.

“It is causing increasing case counts in certain parts of the world, including India. We’re not seeing high rates of XBB.1.16 yet in the United States, but it may become more prominent in coming weeks,” Mayo Clinic viral disease expert Matthew Binnicker, PhD, told The Seattle Times.

Arcturus has been causing a new symptom in children, Indian medical providers have reported.

“One new feature of cases caused by this variant is that it seems to be causing conjunctivitis, or red and itchy eyes, in young patients,” Dr. Binnicker said. “This is not something that we’ve seen with prior strains of the virus.”

More than 11,000 people in the United States remained hospitalized with COVID at the end of last week, and 1,327 people died of the virus last week, CDC data show. To date, 6.9 million people worldwide have died from COVID, the WHO says. Of those deaths, more than 1.1 million occurred in the U.S.

A version of this article originally appeared on WebMD.com.

The new COVID-19 strain known as “Arcturus” has increased in the United States so much that it has been added to the Centers for Disease and Control’s watch list.

Officially labeled XBB.1.16, Arcturus is a subvariant of Omicron that was first seen in India and has been on the World Health Organization’s watchlist since the end of March. The CDC’s most recent update now lists Arcturus as causing 7% of U.S. coronavirus cases, landing it in second place behind its long-predominant Omicron cousin XBB.1.5, which causes 78% of cases.

Arcturus is more transmissible but not more dangerous than recent chart-topping strains, experts say.

“It is causing increasing case counts in certain parts of the world, including India. We’re not seeing high rates of XBB.1.16 yet in the United States, but it may become more prominent in coming weeks,” Mayo Clinic viral disease expert Matthew Binnicker, PhD, told The Seattle Times.

Arcturus has been causing a new symptom in children, Indian medical providers have reported.

“One new feature of cases caused by this variant is that it seems to be causing conjunctivitis, or red and itchy eyes, in young patients,” Dr. Binnicker said. “This is not something that we’ve seen with prior strains of the virus.”

More than 11,000 people in the United States remained hospitalized with COVID at the end of last week, and 1,327 people died of the virus last week, CDC data show. To date, 6.9 million people worldwide have died from COVID, the WHO says. Of those deaths, more than 1.1 million occurred in the U.S.

A version of this article originally appeared on WebMD.com.

The 30-second commercial, part of the government’s We Can Do This campaign, shows everyday people going about their lives, then reminds them that, “because COVID is still out there and so are you,” it might be time to update your vaccine.

But in real life, the message that COVID-19 is still a major concern is muffled if not absent for many. Many data tracking sources, both federal and others, are no longer reporting, as often, the number of COVID cases, hospitalizations, and deaths. 

The Department of Health & Human Services in February stopped updating its public COVID data site, instead directing all queries to the Centers for Disease Control and Prevention, which itself has been updating only weekly instead of daily since 2022. 

Nongovernmental sources, such as John Hopkins University, stopped reporting pandemic data in March, The New York Times also ended its COVID data-gathering project in March, stating that “the comprehensive real-time reporting that The Times has prioritized is no longer possible.” It will rely on reporting weekly CDC data moving forward. 

Along with the tracking sites, masking and social distancing mandates have mostly disappeared. President Joe Biden signed a bipartisan bill on April 10 that ended the national emergency for COVID. While some programs will stay in place for now, such as free vaccines, treatments, and tests, that too will go away when the federal public health emergency expires on May 11. The HHS already has issued its transition roadmap.

Many Americans, meanwhile, are still on the fence about the pandemic. A Gallup poll from March shows that about half of the American public say it’s over, and about half disagree. 

Are we closing up shop on COVID-19 too soon, or is it time? Not surprisingly, experts don’t agree. Some say the pandemic is now endemic – which broadly means the virus and its patterns are predictable and steady in designated regions – and that it’s critical to catch up on health needs neglected during the pandemic, such as screenings and other vaccinations

But others don’t think it’s reached that stage yet, saying that we are letting our guard down too soon and we can’t be blind to the possibility of another strong variant – or pandemic – emerging. Surveillance must continue, not decline, and be improved.
 

Time to move on?

In its transition roadmap released in February, the HHS notes that daily COVID reported cases are down over 90%, compared with the peak of the Omicron surge at the end of January 2022; deaths have declined by over 80%; and new hospitalizations caused by COVID have dropped by nearly 80%.

It is time to move on, said Ali Mokdad, PhD, a professor and chief strategy officer of population health at the Institute for Health Metrics and Evaluation at the University of Washington, Seattle. 

“Many people were delaying a lot of medical care, because they were afraid” during COVID’s height, he said, explaining that elective surgeries were postponed, prenatal care went down, as did screenings for blood pressure and diabetes.

His institute was tracking COVID projections every week but stopped in December.

As for emerging variants, “we haven’t seen a variant that scares us since Omicron” in November 2021, said Dr. Mokdad, who agrees that COVID is endemic now. The subvariants that followed it are very similar, and the current vaccines are working. 

“We can move on, but we cannot drop the ball on keeping an eye on the genetic sequencing of the virus,” he said. That will enable quick identification of new variants.

If a worrisome new variant does surface, Dr. Mokdad said, certain locations and resources will be able to gear up quickly, while others won’t be as fast, but overall the United States is in a much better position now. 

Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, Baltimore, also believes the pandemic phase is behind us

“This can’t be an emergency in perpetuity,” he said “Just because something is not a pandemic [anymore] does not mean that all activities related to it cease.”

COVID is highly unlikely to overwhelm hospitals again, and that was the main reason for the emergency declaration, he said. 

“It’s not all or none – collapsing COVID-related [monitoring] activities into the routine monitoring that is done for other infectious disease should be seen as an achievement in taming the virus,” he said.
 

Not endemic yet

Closing up shop too early could mean we are blindsided, said Rajendram Rajnarayanan, PhD, an assistant dean of research and associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University in Jonesboro. 

Already, he said, large labs have closed or scaled down as testing demand has declined, and many centers that offered community testing have also closed. Plus, home test results are often not reported.

Continued monitoring is key, he said. “You have to maintain a base level of sequencing for new variants,” he said. “Right now, the variant that is ‘top dog’ in the world is XBB.1.16.” 

That’s an Omicron subvariant that the World Health Organization is currently keeping its eye on, according to a media briefing on March 29. There are about 800 sequences of it from 22 countries, mostly India, and it’s been in circulation a few months. 

Dr. Rajnarayanan said he’s not overly worried about this variant, but surveillance must continue. His own breakdown of XBB.1.16 found the subvariant in 27 countries, including the United States, as of April 10.

Ideally, Dr. Rajnarayanan would suggest four areas to keep focusing on, moving forward:

• Active, random surveillance for new variants, especially in hot spots.
• Hospital surveillance and surveillance of long-term care, especially in congregate settings where people can more easily spread the virus.
• Travelers’ surveillance, now at , according to the CDC.
• Surveillance of animals such as mink and deer, because these animals can not only pick up the virus, but the virus can mutate in the animals, which could then transmit it back to people. 

With less testing, baseline surveillance for new variants has declined. The other three surveillance areas need improvement, too, he said, as the reporting is often delayed. 

Continued surveillance is crucial, agreed Katelyn Jetelina, PhD, an epidemiologist and data scientist who publishes a newsletter, Your Local Epidemiologist, updating developments in COVID and other pressing health issues. 

“It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars,” said Dr. Jetelina, who is also director of population health analytics for the Meadows Mental Health Policy Institute. “COVID-19 is still going to be here, it’s still going to mutate,” and still cause grief for those affected. “I’m most concerned about our ability to track the virus. It’s not clear what surveillance we will still have in the states and around the globe.” 

It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars.

For surveillance, she calls wastewater monitoring “the lowest-hanging fruit.” That’s because it “is not based on bias testing and has the potential to help with other outbreaks, too.” Hospitalization data is also essential, she said, as that information is the basis for public health decisions on updated vaccines and other protective measures.

While Dr. Jetelina is hopeful that COVID will someday be universally viewed as endemic, with predictable seasonal patterns, “I don’t think we are there yet. We still need to approach this virus with humility; that’s at least what I will continue to do.”

Dr. Rajnarayanan agreed that the pandemic has not yet reached endemic phase, though the situation is much improved. “Our vaccines are still protecting us from severe disease and hospitalization, and [the antiviral drug] Paxlovid is a great tool that works.”
 

Keeping tabs

While some data tracking has been eliminated, not all has, or will be. The CDC, as mentioned, continues to post cases, deaths, and a daily average of new hospital admissions weekly. The WHO’s dashboard tracks deaths, cases, and vaccine doses globally. 

In March, the WHO updated its working definitions and tracking system for SARS-CoV-2 variants of concern and variants of interest, with goals of evaluating the sublineages independently and to classify new variants more clearly when that’s needed. 

Still, WHO is considering ending its declaration of COVID as a public health emergency of international concern sometime in 2023.

Some public companies are staying vigilant. The drugstore chain Walgreens said it plans to maintain its COVID-19 Index, which launched in January 2022. 

“Data regarding spread of variants is important to our understanding of viral transmission and, as new variants emerge, it will be critical to continue to track this information quickly to predict which communities are most at risk,” Anita Patel, PharmD, vice president of pharmacy services development for Walgreens, said in a statement.

The data also reinforces the importance of vaccinations and testing in helping to stop the spread of COVID-19, she said.

A version of this article first appeared on WebMD.com.

The 30-second commercial, part of the government’s We Can Do This campaign, shows everyday people going about their lives, then reminds them that, “because COVID is still out there and so are you,” it might be time to update your vaccine.

But in real life, the message that COVID-19 is still a major concern is muffled if not absent for many. Many data tracking sources, both federal and others, are no longer reporting, as often, the number of COVID cases, hospitalizations, and deaths. 

The Department of Health & Human Services in February stopped updating its public COVID data site, instead directing all queries to the Centers for Disease Control and Prevention, which itself has been updating only weekly instead of daily since 2022. 

Nongovernmental sources, such as John Hopkins University, stopped reporting pandemic data in March, The New York Times also ended its COVID data-gathering project in March, stating that “the comprehensive real-time reporting that The Times has prioritized is no longer possible.” It will rely on reporting weekly CDC data moving forward. 

Along with the tracking sites, masking and social distancing mandates have mostly disappeared. President Joe Biden signed a bipartisan bill on April 10 that ended the national emergency for COVID. While some programs will stay in place for now, such as free vaccines, treatments, and tests, that too will go away when the federal public health emergency expires on May 11. The HHS already has issued its transition roadmap.

Many Americans, meanwhile, are still on the fence about the pandemic. A Gallup poll from March shows that about half of the American public say it’s over, and about half disagree. 

Are we closing up shop on COVID-19 too soon, or is it time? Not surprisingly, experts don’t agree. Some say the pandemic is now endemic – which broadly means the virus and its patterns are predictable and steady in designated regions – and that it’s critical to catch up on health needs neglected during the pandemic, such as screenings and other vaccinations

But others don’t think it’s reached that stage yet, saying that we are letting our guard down too soon and we can’t be blind to the possibility of another strong variant – or pandemic – emerging. Surveillance must continue, not decline, and be improved.
 

Time to move on?

In its transition roadmap released in February, the HHS notes that daily COVID reported cases are down over 90%, compared with the peak of the Omicron surge at the end of January 2022; deaths have declined by over 80%; and new hospitalizations caused by COVID have dropped by nearly 80%.

It is time to move on, said Ali Mokdad, PhD, a professor and chief strategy officer of population health at the Institute for Health Metrics and Evaluation at the University of Washington, Seattle. 

“Many people were delaying a lot of medical care, because they were afraid” during COVID’s height, he said, explaining that elective surgeries were postponed, prenatal care went down, as did screenings for blood pressure and diabetes.

His institute was tracking COVID projections every week but stopped in December.

As for emerging variants, “we haven’t seen a variant that scares us since Omicron” in November 2021, said Dr. Mokdad, who agrees that COVID is endemic now. The subvariants that followed it are very similar, and the current vaccines are working. 

“We can move on, but we cannot drop the ball on keeping an eye on the genetic sequencing of the virus,” he said. That will enable quick identification of new variants.

If a worrisome new variant does surface, Dr. Mokdad said, certain locations and resources will be able to gear up quickly, while others won’t be as fast, but overall the United States is in a much better position now. 

Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, Baltimore, also believes the pandemic phase is behind us

“This can’t be an emergency in perpetuity,” he said “Just because something is not a pandemic [anymore] does not mean that all activities related to it cease.”

COVID is highly unlikely to overwhelm hospitals again, and that was the main reason for the emergency declaration, he said. 

“It’s not all or none – collapsing COVID-related [monitoring] activities into the routine monitoring that is done for other infectious disease should be seen as an achievement in taming the virus,” he said.
 

Not endemic yet

Closing up shop too early could mean we are blindsided, said Rajendram Rajnarayanan, PhD, an assistant dean of research and associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University in Jonesboro. 

Already, he said, large labs have closed or scaled down as testing demand has declined, and many centers that offered community testing have also closed. Plus, home test results are often not reported.

Continued monitoring is key, he said. “You have to maintain a base level of sequencing for new variants,” he said. “Right now, the variant that is ‘top dog’ in the world is XBB.1.16.” 

That’s an Omicron subvariant that the World Health Organization is currently keeping its eye on, according to a media briefing on March 29. There are about 800 sequences of it from 22 countries, mostly India, and it’s been in circulation a few months. 

Dr. Rajnarayanan said he’s not overly worried about this variant, but surveillance must continue. His own breakdown of XBB.1.16 found the subvariant in 27 countries, including the United States, as of April 10.

Ideally, Dr. Rajnarayanan would suggest four areas to keep focusing on, moving forward:

• Active, random surveillance for new variants, especially in hot spots.
• Hospital surveillance and surveillance of long-term care, especially in congregate settings where people can more easily spread the virus.
• Travelers’ surveillance, now at , according to the CDC.
• Surveillance of animals such as mink and deer, because these animals can not only pick up the virus, but the virus can mutate in the animals, which could then transmit it back to people. 

With less testing, baseline surveillance for new variants has declined. The other three surveillance areas need improvement, too, he said, as the reporting is often delayed. 

Continued surveillance is crucial, agreed Katelyn Jetelina, PhD, an epidemiologist and data scientist who publishes a newsletter, Your Local Epidemiologist, updating developments in COVID and other pressing health issues. 

“It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars,” said Dr. Jetelina, who is also director of population health analytics for the Meadows Mental Health Policy Institute. “COVID-19 is still going to be here, it’s still going to mutate,” and still cause grief for those affected. “I’m most concerned about our ability to track the virus. It’s not clear what surveillance we will still have in the states and around the globe.” 

It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars.

For surveillance, she calls wastewater monitoring “the lowest-hanging fruit.” That’s because it “is not based on bias testing and has the potential to help with other outbreaks, too.” Hospitalization data is also essential, she said, as that information is the basis for public health decisions on updated vaccines and other protective measures.

While Dr. Jetelina is hopeful that COVID will someday be universally viewed as endemic, with predictable seasonal patterns, “I don’t think we are there yet. We still need to approach this virus with humility; that’s at least what I will continue to do.”

Dr. Rajnarayanan agreed that the pandemic has not yet reached endemic phase, though the situation is much improved. “Our vaccines are still protecting us from severe disease and hospitalization, and [the antiviral drug] Paxlovid is a great tool that works.”
 

Keeping tabs

While some data tracking has been eliminated, not all has, or will be. The CDC, as mentioned, continues to post cases, deaths, and a daily average of new hospital admissions weekly. The WHO’s dashboard tracks deaths, cases, and vaccine doses globally. 

In March, the WHO updated its working definitions and tracking system for SARS-CoV-2 variants of concern and variants of interest, with goals of evaluating the sublineages independently and to classify new variants more clearly when that’s needed. 

Still, WHO is considering ending its declaration of COVID as a public health emergency of international concern sometime in 2023.

Some public companies are staying vigilant. The drugstore chain Walgreens said it plans to maintain its COVID-19 Index, which launched in January 2022. 

“Data regarding spread of variants is important to our understanding of viral transmission and, as new variants emerge, it will be critical to continue to track this information quickly to predict which communities are most at risk,” Anita Patel, PharmD, vice president of pharmacy services development for Walgreens, said in a statement.

The data also reinforces the importance of vaccinations and testing in helping to stop the spread of COVID-19, she said.

A version of this article first appeared on WebMD.com.

The 30-second commercial, part of the government’s We Can Do This campaign, shows everyday people going about their lives, then reminds them that, “because COVID is still out there and so are you,” it might be time to update your vaccine.

But in real life, the message that COVID-19 is still a major concern is muffled if not absent for many. Many data tracking sources, both federal and others, are no longer reporting, as often, the number of COVID cases, hospitalizations, and deaths. 

The Department of Health & Human Services in February stopped updating its public COVID data site, instead directing all queries to the Centers for Disease Control and Prevention, which itself has been updating only weekly instead of daily since 2022. 

Nongovernmental sources, such as John Hopkins University, stopped reporting pandemic data in March, The New York Times also ended its COVID data-gathering project in March, stating that “the comprehensive real-time reporting that The Times has prioritized is no longer possible.” It will rely on reporting weekly CDC data moving forward. 

Along with the tracking sites, masking and social distancing mandates have mostly disappeared. President Joe Biden signed a bipartisan bill on April 10 that ended the national emergency for COVID. While some programs will stay in place for now, such as free vaccines, treatments, and tests, that too will go away when the federal public health emergency expires on May 11. The HHS already has issued its transition roadmap.

Many Americans, meanwhile, are still on the fence about the pandemic. A Gallup poll from March shows that about half of the American public say it’s over, and about half disagree. 

Are we closing up shop on COVID-19 too soon, or is it time? Not surprisingly, experts don’t agree. Some say the pandemic is now endemic – which broadly means the virus and its patterns are predictable and steady in designated regions – and that it’s critical to catch up on health needs neglected during the pandemic, such as screenings and other vaccinations

But others don’t think it’s reached that stage yet, saying that we are letting our guard down too soon and we can’t be blind to the possibility of another strong variant – or pandemic – emerging. Surveillance must continue, not decline, and be improved.
 

Time to move on?

In its transition roadmap released in February, the HHS notes that daily COVID reported cases are down over 90%, compared with the peak of the Omicron surge at the end of January 2022; deaths have declined by over 80%; and new hospitalizations caused by COVID have dropped by nearly 80%.

It is time to move on, said Ali Mokdad, PhD, a professor and chief strategy officer of population health at the Institute for Health Metrics and Evaluation at the University of Washington, Seattle. 

“Many people were delaying a lot of medical care, because they were afraid” during COVID’s height, he said, explaining that elective surgeries were postponed, prenatal care went down, as did screenings for blood pressure and diabetes.

His institute was tracking COVID projections every week but stopped in December.

As for emerging variants, “we haven’t seen a variant that scares us since Omicron” in November 2021, said Dr. Mokdad, who agrees that COVID is endemic now. The subvariants that followed it are very similar, and the current vaccines are working. 

“We can move on, but we cannot drop the ball on keeping an eye on the genetic sequencing of the virus,” he said. That will enable quick identification of new variants.

If a worrisome new variant does surface, Dr. Mokdad said, certain locations and resources will be able to gear up quickly, while others won’t be as fast, but overall the United States is in a much better position now. 

Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, Baltimore, also believes the pandemic phase is behind us

“This can’t be an emergency in perpetuity,” he said “Just because something is not a pandemic [anymore] does not mean that all activities related to it cease.”

COVID is highly unlikely to overwhelm hospitals again, and that was the main reason for the emergency declaration, he said. 

“It’s not all or none – collapsing COVID-related [monitoring] activities into the routine monitoring that is done for other infectious disease should be seen as an achievement in taming the virus,” he said.
 

Not endemic yet

Closing up shop too early could mean we are blindsided, said Rajendram Rajnarayanan, PhD, an assistant dean of research and associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University in Jonesboro. 

Already, he said, large labs have closed or scaled down as testing demand has declined, and many centers that offered community testing have also closed. Plus, home test results are often not reported.

Continued monitoring is key, he said. “You have to maintain a base level of sequencing for new variants,” he said. “Right now, the variant that is ‘top dog’ in the world is XBB.1.16.” 

That’s an Omicron subvariant that the World Health Organization is currently keeping its eye on, according to a media briefing on March 29. There are about 800 sequences of it from 22 countries, mostly India, and it’s been in circulation a few months. 

Dr. Rajnarayanan said he’s not overly worried about this variant, but surveillance must continue. His own breakdown of XBB.1.16 found the subvariant in 27 countries, including the United States, as of April 10.

Ideally, Dr. Rajnarayanan would suggest four areas to keep focusing on, moving forward:

• Active, random surveillance for new variants, especially in hot spots.
• Hospital surveillance and surveillance of long-term care, especially in congregate settings where people can more easily spread the virus.
• Travelers’ surveillance, now at , according to the CDC.
• Surveillance of animals such as mink and deer, because these animals can not only pick up the virus, but the virus can mutate in the animals, which could then transmit it back to people. 

With less testing, baseline surveillance for new variants has declined. The other three surveillance areas need improvement, too, he said, as the reporting is often delayed. 

Continued surveillance is crucial, agreed Katelyn Jetelina, PhD, an epidemiologist and data scientist who publishes a newsletter, Your Local Epidemiologist, updating developments in COVID and other pressing health issues. 

“It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars,” said Dr. Jetelina, who is also director of population health analytics for the Meadows Mental Health Policy Institute. “COVID-19 is still going to be here, it’s still going to mutate,” and still cause grief for those affected. “I’m most concerned about our ability to track the virus. It’s not clear what surveillance we will still have in the states and around the globe.” 

It’s a bit ironic to have a date for the end of a public health emergency; viruses don’t care about calendars.

For surveillance, she calls wastewater monitoring “the lowest-hanging fruit.” That’s because it “is not based on bias testing and has the potential to help with other outbreaks, too.” Hospitalization data is also essential, she said, as that information is the basis for public health decisions on updated vaccines and other protective measures.

While Dr. Jetelina is hopeful that COVID will someday be universally viewed as endemic, with predictable seasonal patterns, “I don’t think we are there yet. We still need to approach this virus with humility; that’s at least what I will continue to do.”

Dr. Rajnarayanan agreed that the pandemic has not yet reached endemic phase, though the situation is much improved. “Our vaccines are still protecting us from severe disease and hospitalization, and [the antiviral drug] Paxlovid is a great tool that works.”
 

Keeping tabs

While some data tracking has been eliminated, not all has, or will be. The CDC, as mentioned, continues to post cases, deaths, and a daily average of new hospital admissions weekly. The WHO’s dashboard tracks deaths, cases, and vaccine doses globally. 

In March, the WHO updated its working definitions and tracking system for SARS-CoV-2 variants of concern and variants of interest, with goals of evaluating the sublineages independently and to classify new variants more clearly when that’s needed. 

Still, WHO is considering ending its declaration of COVID as a public health emergency of international concern sometime in 2023.

Some public companies are staying vigilant. The drugstore chain Walgreens said it plans to maintain its COVID-19 Index, which launched in January 2022. 

“Data regarding spread of variants is important to our understanding of viral transmission and, as new variants emerge, it will be critical to continue to track this information quickly to predict which communities are most at risk,” Anita Patel, PharmD, vice president of pharmacy services development for Walgreens, said in a statement.

The data also reinforces the importance of vaccinations and testing in helping to stop the spread of COVID-19, she said.

A version of this article first appeared on WebMD.com.