Asthma and COVID-19 in children: A systematic review and call for data

Rationale: Whether asthma constitutes a risk factor for coronavirus disease-2019 (COVID-19) is unclear. Here, we aimed to assess whether asthma, the most common chronic disease in children, is associated with higher COVID-19 risk or severity in pediatric populations. Methods: We performed a systematic literature search in three stages: first, we reviewed PubMed, EMBASE, and CINAHL for systematic reviews of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and COVID-19 in pediatric populations, and reviewed their primary articles; second, we searched PubMed for studies on COVID-19 or SARS-CoV-2 and asthma/wheeze, and evaluated whether the resulting studies included pediatric populations; third, we repeated the second search in and to find pre-prints that may have information on pediatric asthma. Results: In the first search, eight systematic reviews were found, of which five were done in pediatric populations; none of the 67 primary studies included data on pediatric asthma as a comorbidity for COVID-19. In the second search, we found 34 results in PubMed, of which five reported asthma in adults, but none included data on children. In the third search, 25 pre-prints in MedRxiv included data on asthma, but none on children. We found one report by the US Centers for Disease Control and Prevention stating that 40/345 (similar to 11.5%) children with data on chronic conditions had "chronic lung diseases including asthma," and one from a tertiary hospital in New York that reported asthma in 11/46 (similar to 23.9%) children hospitalized for COVID-19. Conclusion: There is scarcely any data on whether childhood asthma (or other pediatric respiratory diseases) constitute risk factors for SARS-CoV-2 infection or COVID-19 severity. Studies are needed that go beyond counting the number of cases in the pediatric age range.