Bronchiolitis 2021-2022 epidemic: multicentric analysis of the characteristics and treatment approach in 214 children from different areas in Italy.

Bronchiolitis causes a remarkable number of hospitalizations; its epidemiology follows that of respiratory syncytial virus (RSV), its main pathogen. The aim of this study was to evaluate the presenting features, treatment approach, and impact of medical therapy in four pediatric hospitals in Italy. Data on infants < 24 months of age hospitalized with bronchiolitis in the 2021-2022 season were collected. Between October 2021 and February 2022, 214 children were admitted. Median hospital stay was 5 days; none of the patients died. The distribution of the presenting features is largely comparable in the 33 (15.8%) RSV-negative versus the 176 (84.2%) RSV-positive children; also, no difference was observed in medical therapy provided: duration of oxygen therapy, administration of steroid, and duration of hospital stay. Systemic steroids, inhalation, or antibiotic therapy were given to 34.6%, 79.4%, and 49.1% of children respectively. Of the 214 patients with bronchiolitis, only 19 (8.8%) were admitted to ICU.   Conclusion: Our data suggest that, irrespective of treatments provided, RSV-positive and RSV-negative children had a similar clinical course. The results of our retrospective study further underline the need to improve adherence to existing guidelines on bronchiolitis treatment. What is Known: • Bronchiolitis is a common diseases with seasonal peak. The outcome is usually favorable but hospitalization and even ICU admission is not exceptional. What is New: • Children with RSV associated bronchiolitis do not have a different course and outcome. The analysis of the 2021-2022 cohort, following COVID pandemic peaking, did not show a different course and outcome. • Adherence to literature recommendation, i.e. to focus on oxygen and hydration therapy while avoiding unnecessary systemic therapy with steroid and antibiotics, should be improved.