In one of several recently published studies on the relationship between COVID-19 infection and asthma, according to data drawn from the National Survey of Children’s Health (NSCH).
The inverse correlation between symptoms and vaccination was strong and statistically significant, according to investigators led by Matthew M. Davis, MD, Physician in Chief and Chief Scientific Officer, Nemours Children’s Health, Wilmington, Delaware.
“With each increase of 10 percentage points in COVID-19 vaccination coverage, the parent-reported child asthma symptoms prevalence decreased by 0.36 percentage points (P < .05),” Dr. Davis and his coinvestigators reported in a research letter published in JAMA Network Open.
Studies Explore Relationship of COVID and Asthma
The reduced risk of asthma symptoms with COVID-19 vaccination in children at the population level is just one of several recently published studies exploring the interaction between COVID-19 infection and asthma, but two studies that posed the same question did not reach the same conclusion.
In one, COVID-19 infection in children was not found to be a trigger for new-onset asthma, but the second found that it was. In a third study, the preponderance of evidence from a meta-analysis found that patients with asthma – whether children or adults – did not necessarily experience a more severe course of COVID-19 infection than in those without asthma.
The NSCH database study calculated state-level change in scores for patient-reported childhood asthma symptoms in the years in the years 2018-2019, which preceded the pandemic and the years 2020-2021, when the pandemic began. The hypothesis was that the proportion of the population 5 years of age or older who completed the COVID-19 primary vaccination would be inversely related to asthma symptom prevalence.
Relative to the 2018-2019 years, the mean rate of parent-reported asthma symptoms was 0.85% lower (6.93% vs 7.77%; P < .001) in 2020-2021, when the mean primary series COVID-19 vaccination rate was 72.3%.
The study was not able to evaluate the impact of COVID-19 vaccination specifically in children with asthma, because history of asthma is not captured in the NSCH data, but Dr. Davis contended that the reduction in symptomatic asthma among children with increased vaccination offers validation for the state-level findings.
“Moreover, the absence of an association of COVID-19 vaccination administered predominantly in 2021 with population-level COVID-19 mortality in 2020 serves as a negative control,” he and his colleagues wrote in their research letter.
Protection from Respiratory Viruses Seen for Asthma Patients
In an interview, Dr. Davis reported that these data are consistent with previous evidence that immunization against influenza also reduces risk of asthma symptoms. In a meta-analysis published in 2017, it was estimated that live vaccines reduced risk of influenza by 81% and prevented 59%-72% of asthma attacks leading to hospitalizations or emergency room visits.
“The similarity of our findings regarding COVID-19 vaccination to prior data regarding influenza vaccination underscores the importance of preventing viral illnesses in individuals with a history of asthma,” Dr. Davis said. It is not yet clear if this is true of respiratory syncytial virus (RSV). Because of the short time that the RSV vaccine has been available, it is too soon to conduct an analysis.
One message from this study is that “clinicians should continue to encourage COVID-19 vaccination for children because of its general benefits in preventing coronavirus-related illness and the apparent specific benefits for children with a history of asthma,” he said.
While vaccination appears to reduce asthmatic symptoms related to COVID-19 infection, one study suggests that COVID-19 does not trigger new-onset asthma. In a retrospective study published in Pediatrics, no association between COVID-19 infection and new-onset asthma could be made in an analysis of 27,423 children (ages, 1-16 years) from the Children’s Hospital of Philadelphia (CHOP) Care Network.
Across all the pediatric age groups evaluated, the consistent finding was “SARS-CoV-2 positivity does not confer an additional risk for asthma diagnosis at least within the first 18 months after a [polymerase chain reaction] test,” concluded the investigators, led by David A. Hill, MD, PhD, Division of Allergy and Immunology, CHOP, Philadelphia, Pennsylvania.