Epidemiological and Clinical Features of Bronchiolitis after the COVID-19 Outbreak: Comparison of Two Epidemic Seasons.

BACKGROUND:The first aim of this study was to compare Pediatric Emergency Department (PED) admissions for acute bronchiolitis during the 2022-2023 season to those of the season 2021-2022. The secondary aim was to assess the difference in the recurrence of bronchiolitis episodes in the same patient between the two seasons. METHODS:This is a retrospective, observational, cross-sectional study conducted at the PED of IRCCS A. Gemelli University Polyclinic Foundation (Rome, Italy). We included all children aged between 0 and 2 years admitted to PED with the diagnosis of bronchiolitis. We compared features of seasons 2021-2022 and 2022-2023. RESULTS:The median age of children enrolled during the 2022-23 season was 5 months (IQR: 2-8) compared to 7 months (IQR: 2-14) in the previous one (P=0.02). We observed in the last season a higher number of children admitted to PED with a high priority code and an increased therapeutic use of high-flow nasal cannula and inhaled adrenaline. During the 2022-23 season we found 31 (12.8%) children presenting more than one episode of bronchiolitis in the same epidemic season, compared to 16 (7.6%) children in the previous season (P=0.048). CONCLUSIONS:Our data emphasize that the epidemiological features of bronchiolitis after COVID-19 outbreak have changed and are still evolving.