The prevalence of long COVID in children has been unclear, and is complicated by the lack of a consistent definition, said Anna Funk, PhD, an epidemiologist at the University of Calgary (Alba.), during her online presentation of the findings at the 31st European Congress of Clinical Microbiology & Infectious Diseases.
In the several small studies conducted to date, rates range from 0% to 67% 2-4 months after infection, Dr. Funk reported.
To examine prevalence, she and her colleagues, as part of the Pediatric Emergency Research Network (PERN) global research consortium, assessed more than 10,500 children who were screened for SARS-CoV-2 when they presented to the ED at 1 of 41 study sites in 10 countries – Australia, Canada, Indonesia, the United States, plus three countries in Latin America and three in Western Europe – from March 2020 to June 15, 2021.
PERN researchers are following up with the more than 3,100 children who tested positive 14, 30, and 90 days after testing, tracking respiratory, neurologic, and psychobehavioral sequelae.
Dr. Funk presented data on the 1,884 children who tested positive for SARS-CoV-2 before Jan. 20, 2021, and who had completed 90-day follow-up; 447 of those children were hospitalized and 1,437 were not.
Symptoms were reported more often by children admitted to the hospital than not admitted (9.8% vs. 4.6%). Common persistent symptoms were respiratory in 2% of cases, systemic (such as fatigue and fever) in 2%, neurologic (such as headache, seizures, and continued loss of taste or smell) in 1%, and psychological (such as new-onset depression and anxiety) in 1%.
“This study provides the first good epidemiological data on persistent symptoms among SARS-CoV-2–infected children, regardless of severity,” said Kevin Messacar, MD, a pediatric infectious disease clinician and researcher at Children’s Hospital Colorado in Aurora, who was not involved in the study.
And the findings show that, although severe COVID and chronic symptoms are less common in children than in adults, they are “not nonexistent and need to be taken seriously,” he said in an interview.
After adjustment for country of enrollment, children aged 10-17 years were more likely to experience persistent symptoms than children younger than 1 year (odds ratio, 2.4; P = .002).
Hospitalized children were more than twice as likely to experience persistent symptoms as nonhospitalized children (OR, 2.5; P < .001). And children who presented to the ED with at least seven symptoms were four times more likely to have long-term symptoms than those who presented with fewer symptoms (OR, 4.02; P = .01).
‘Some reassurance’
“Given that COVID is new and is known to have acute cardiac and neurologic effects, particularly in children with [multisystem inflammatory syndrome], there were initially concerns about persistent cardiovascular and neurologic effects in any infected child,” Dr. Messacar explained. “These data provide some reassurance that this is uncommon among children with mild or moderate infections who are not hospitalized.”
But “the risk is not zero,” he added. “Getting children vaccinated when it is available to them and taking precautions to prevent unvaccinated children getting COVID is the best way to reduce the risk of severe disease or persistent symptoms.”
The study was limited by its lack of data on variants, reliance on self-reported symptoms, and a population drawn solely from EDs, Dr. Funk acknowledged.
No external funding source was noted. Dr. Messacar and Dr. Funk disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.