Influence of the COVID-19 pandemic on the distribution of acute bronchiolitis in Spain

BACKGROUND // Bronchiolitis is the leading cause of hospitalization in children under one year of age, with annual epidemics. Since the onset of the SARS-CoV-2 coronavirus disease pandemic (COVID-19), there has been a change in the transmission of other respiratory viruses. Our aim in this paper was to describe how COVID-19 had affected the distribution of acute bronchiolitis in our country.METHODS // We conducted a retrospective descriptive study of the cases of bronchiolitis treated in a sample of Spanish hospitals belonging to four autonomous communities. A chi-square test and Student's t- test were used to compare epidemiological and demographic variables between patients attending the hospital with bronchiolitis during January 2021-June 2021 with patients attending the hospital in the previous three years (2018-2020).RESULTS // We analyzed 6,124 cases of bronchiolitis (58.8% males and 41.2% females). The mean age was 0.5 years (SD: 0.4). In 2020, we observed a decrease of bronchiolitis cases compared to 2019 of 67%. During 2020 and 2021, the epidemic season started in January-February and peaked in June. During the first half of 2021, the highest percentage of admissions for bronchiolitis associated with RSV infection was observed in hospitals in central Spain corresponding to the Autonomous Community of Madrid (78.5% of admissions).CONCLUSIONS // The COVID-19 pandemic significantly modifies the seasonality of bronchiolitis. In our country, the flow and distribution of the disease are not uniform. It starts in the center of Spain and ends on the coast