Objective Pediatric asthma is multifactorial: social, environmental, and infectious exposures trigger exacerbations. Policies adopted to mitigate COVID-19 transmission in schools including school closures, mask mandates, and full reopening, provide a natural experiment to investigate the importance of socially-driven exposures, including viral transmission, in pediatric asthma.

Methods This observational study used retrospective review of all electronic health records from the largest urban health system in New York City over five school years from 2018-2023. We investigated the epidemiology of acute, unscheduled care for pediatric asthma in children ages 5-17 years, including emergency department (ED) visits, hospital admissions, intensive care unit (ICU) stays, and viral testing. Comparison groups were drawn from citywide surveillance data and all-cause visits. We investigated population-level exposures: COVID-19 mitigation policies and wildfire smoke events.

Results In the post-pandemic period, ED volume for pediatric asthma dropped (p<0.0001); however, children who presented were significantly more likely to require hospital admission and ICU care (p<0.001). Viral testing was employed more frequently, and more frequently positive, in the post-pandemic period (p<0.0001), with rhinovirus driving a greater proportion of pediatric asthma than all-cause adult or pediatric visits (p=0.02). After mask mandates were dropped in early 2022, pediatric asthma peaked during the immediate return-to-school fall period, slightly preceding the winter 2022 peak in viral illnesses. Wildfire smoke events were not significantly associated with pediatric asthma visits.

Conclusions Socially-driven factors including viral transmission and school policies were important in driving pediatric asthma during and after the COVID-19 pandemic. Increased acuity despite lower volumes may help guide health systems as they strive to increase readiness to care for pediatric populations.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB of Icahn School of Medicine at Mount Sinai gave ethical approval for this work.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors, subject to institutional policies.