Seasonal Patterns of Hospitalizations for Pediatric Acute Respiratory Diseases by Age Group and Sex in Alberta, Canada: A Population-Level Retrospective Cohort Study From 2010 to 2025.

After the near disappearance of pediatric acute respiratory disease (ARD) hospitalizations during the COVID-19 pandemic (2020-2021), during the late-pandemic (2022-2023), only the resurgence in bronchiolitis, including both age groups and sexes, exceeded seasonal autoregressive integrated moving average model reference ranges. Two full seasons post-pandemic (2023-2024, 2024-2025), pediatric ARD hospitalizations remained within SARIMA model reference ranges developed on pre-pandemic patterns.