IMPACT OF THE COVID-19 PANDEMIC ON THE DYNAMICS OF HOSPITALIZATIONS FOR ACUTE BRONCHITIS AND ACUTE BRONCHIOLITIS IN CHILDREN UNDER FOUR YEARS OF AGE IN BRAZIL: A TIME-SERIES STUDY (2015–2025)

Abstract

Acute bronchiolitis is one of the leading causes of hospitalization for respiratory infections in young children, and its epidemiological dynamics were substantially altered by the non-pharmacological interventions adopted during the COVID-19 pandemic. This study aimed to analyze the impact of the pandemic on hospitalizations for acute bronchitis and acute bronchiolitis among children under four years of age in Brazil from 2015 to 2025. This ecological, descriptive time-series study used secondary data obtained from the Brazilian Unified Health System Hospital Information System (SIH/SUS-DATASUS). Hospital admissions, deaths, hospitalization rates per 10,000 children, and hospital case-fatality rates were analyzed according to year and Brazilian macro-region. A marked reduction in hospitalizations was observed during 2020 and 2021, followed by progressive recovery and an epidemiological rebound in 2022 and 2023, with subsequent stabilization in 2024 and 2025. The South and Southeast regions showed the highest hospitalization rates, whereas the North and Northeast presented the highest case-fatality rates, highlighting persistent regional inequalities in pediatric healthcare. Despite substantial fluctuations in hospital admissions, case-fatality rates remained relatively low throughout the study period. These findings demonstrate that COVID-19 control measures temporarily altered respiratory virus circulation and changed the epidemiological behavior of bronchiolitis in Brazil. Continuous monitoring of these indicators may support public health surveillance, healthcare planning, and preventive strategies aimed at reducing the burden of respiratory diseases in children.