Background and Objectives:
In the United States (US), an unexpected wave of Respiratory Syncytial Virus (RSV) has hit pediatric wards in 2022. In November 2022, a seasonal increase in RSV cases is also observed in Europe. The present work is a preliminary analysis on the epidemiology of RSV, using data from the Integrated University Hospital of Verona (AOUI VR). We compared the epidemic curve in the 2022-2023 season with the previous ones. Furthermore, the temporal trend will be compared with the current primary epidemiological data (European Centre for Disease Control ECDC and Centre for Disease Control CDC).

Methods:
Data about number of RSV-positive patients were collected via Hospital Discharge Forms of AOUI VR (ICD9-CM diagnosis codes: 079.6, 480.1, and 466.11). We analyzed seasons from 2018-2019 to 2022-2023, with specific focus on the 0-4 age group. ECDCs Atlas platform and CDCs RSV-NET interactive dashboard were compared.

Results:
In 2018-2019 and 2019-2020, the trend of the AOUI RSV remained similar over time: an abrupt start of the epidemic was observed in December, followed by a peak of about 40 monthly hospitalized cases in January and a significant decline in March. Conversely, in 2020-2021, no RSV cases were hospitalized in AOUI. The epidemic resumed in the 2021-2022 season, starting in October, peaking in November and ending in January. In contrast, the first cases of the 2022-2023 season were already detected in September, without any significant increase (<5 new cases monthly) until now. Data collection is in progress.

Conclusions:
Although the RSV epidemic season is still ongoing, differences between 2018-2023 AOUI data and the epidemic trend in the US are detectable. Given these preliminary results, an increased focus on acquiring additional data through a dedicated national surveillance network could significantly improve RSV epidemic management.