ABSTRACT
Background: The coronavirus disease 2019 (COVID-19) pandemic led to daycare and school closures and children staying home for several months. The season of the respiratory viruses have been significantly changed. Aims and objectives: This study aims to assess the course of acute bronchiolitis in Brazil during the 2020-2021 season and compare them with the previous seasons. Method(s): Data from hospitalizations of acute bronchiolitis in infants <1 year were obtained from the Brazilian Public Health database for the period between 2016 and 2021. These data were also analyzed by Brazilian macroregions. The absolute and relative reductions were calculated by analyzing the yearly subsets: 2016-2019 vs 2020, 2016- 2019 vs 2021 and 2020 vs 2021. Result(s): A statiscally significant reduction was observed between 2016-2019 vs 2020, -76% (incidence rate ratio [IRR], 0.23 [95% confidence interval {CI},. 21-.25]) while a significant increase was observed between 2020 vs 2021 +55% (IRR, 0.44 [95% CI,. 40-.48]). Conclusion(s): More than a year into the COVID-19 pandemic, intensified infection control measures have controlled most viral respiratory infections in Brazil. From March to June 2021, however, an increasing number of hospitalizations for acute bronchiolitis were reported in Brazil. This resurgence have probably resulted from restarting social activities for children.