Abstract Purpose: Respiratory Syncytial Virus (RSV) associated infections have historically been the cause of seasonal paediatric hospital departments’ saturation. During the COVID-19 pandemic, the community incidence of RSV was reduced, thus the hospital burden. The last RSV season broke out in early October 2022, 4-6 weeks earlier than in pre-pandemic years, and was thought to be the most demanding to date. Our aim was to assess the burden of RSV-related hospitalizations on a referral hospital (Catalonia, Spain) during the pre-pandemic years and the most recent 2022-2023 season. Methods: We analysed the paediatric hospital and intensive care (PICU) admissions data (January 2016 – January 2023) of a tertiary referral hospital in Catalonia, Spain. All-cause pediatric admissions, admissions related to confirmed RSV infections, and occupancy-related variables were collected. Results and conclusion: RSV-related hospitalizations incidence was lower during the pandemic years, particularly in 2020. The majority of RSV cases within an epidemic peak primarily affected children ≤3 months. Although the number of daily admissions during the last RSV 2022-2023 season was not higher than in the pre-pandemic years, the mean occupancy of the hospital was significantly higher (p= 0.04) due to a longer period of days with more than 20 RSV infected children inpatients per day.

Unraveling the Effects of the COVID-19 Pandemic on the Burden of Respiratory Syncytial Virus in a Tertiary Hospital in Catalonia, Spain: Season 2022-2023 Analysis