Unforeseen changes in seasonality of pediatric respiratory illnesses during the first COVID-19 pandemic year.

Objectives: To investigate whether the three nationwide coronavirus disease 2019 (COVID-19) lockdowns imposed in Israel during the full first pandemic year altered the traditional seasonality of pediatric respiratory healthcare utilization.

Methods: Month by month pediatric emergency department (ED) visits and hospitalizations for respiratory diagnoses during the first full COVID-19 year were compared to those recorded for the six consecutive years preceding the pandemic. Data were collected from the patients' electronic files by utilizing a data extraction platform (MDClone ).

Results: A significant decline of 40% in respiratory ED visits and 54%-73% in respiratory hospitalizations during the first COVID-19 year compared with the pre-COVID-19 years were observed (p < 0.001 and p < 0.001, respectively). The rate of respiratory ED visits out of the total monthly visits, mostly for asthma, peaked during June 2020, compared with proceeding years (109 [5.9%] versus 88 [3.9%] visits; p < 0.001). This peak occurred 2 weeks after the lifting of the first lockdown, resembling the "back-to-school asthma" phenomenon of September.

Conclusions: This study demonstrates important changes in the seasonality of pediatric respiratory illnesses during the first COVID-19 year, including a new "back-from-lockdown" asthma peak. These dramatic changes along with the recent resurgence of respiratory diseases may indicate the beginnings of altered seasonality in pediatric pulmonary pathologies as collateral damage of the pandemic.