Asthma and the Risk of SARS-CoV-2 Infection Among Children and Adolescents

Rao, S.; Hurst, J. H.; Zhao, C.; Goldstein, B. A.; Thomas, L.; Lang, J. E.; Kelly, M. S.

Importance: More than 4 million SARS-COV-2 infections have occurred among children and adolescents in the United States. Risk factors for SARS-CoV-2 infection among children remain poorly defined. Objective: To evaluate the association between asthma and the risk of SARS-CoV-2 infection among children. Design: Retrospective cohort study Setting: A large, integrated health system in central North Carolina. Participants: Children 5 to 17 years of age with a Durham County address and at least one health care encounter in the Duke University Health System between March 1, 2017, and February 28, 2020. Exposure: Diagnosis of asthma Main Outcomes and Measures: The primary outcome was SARS-CoV-2 infection identified by PCR testing of a respiratory sample collected between March 1, 2020, and October 31, 2020. We matched children with asthma 1:1 to children without asthma using propensity scores and used Poisson regression to evaluate the association between asthma and the risk of SARS-CoV-2 infection. We assessed for effect modification of this association by inhaled corticosteroid prescription and comorbid atopic diseases. Results: Of 49,455 children, 6,515 (13%) met criteria for a diagnosis of asthma; all children with asthma were matched to a control child without asthma for a final cohort of 13,030 children. Median (interquartile range) age was 11.0 (8.0, 14.0) years, 56% were male, and 78% were non-White. A diagnosis of asthma was associated with a decreased risk of SARS-CoV-2 infection [risk ratio (RR): 0.67, 95% confidence interval (CI): 0.49-0.92]. This association tended to be stronger in children with asthma who were prescribed inhaled corticosteroids (RR: 0.60, 95% CI: 0.38-0.94) or who had comorbid atopic diseases (RR: 0.59, 95% CI: 0.39-0.88). Of the 66 children with asthma who developed SARS-CoV-2 infection, none required hospitalization for COVID-19. Conclusions and Relevance: Children with asthma had a lower risk of SARS-CoV-2 infection, particularly children prescribed an inhaled corticosteroid or with comorbid atopic diseases. Further studies are needed to explore the complex relationship between asthma, inhaled corticosteroids, and SARS-CoV-2.