Impact of SARS-CoV2 Pandemic and Lockdown on the RSV Circulation: Experience of Three Spoke Hospitals in Northern Italy

The SARS-CoV2 Pandemic affected the global epidemiology of respiratory infections, including Respiratory Syncytial Virus (RSV), thanks to state governments’ implementation of mitigation strategies, like the promotion of face masks and lockdowns. However, after the Pandemic, the dramatic resurge of these diseases was reported worldwide. Our retrospective study, involving three Spoke Pediatric Departments, includes all the infants under one year of age hospitalized for RSV bronchiolitis in a period before the Pandemic period (2017-2020), during the SARS-CoV2 Pandemic (2020-2021) and after the Pandemic (2021-2023). The primary aim was to analyse the temporal trend of RSV in the three periods. Then, clinical and epidemiological characteristics were analysed to highlight clinical differences in the patients affected, in the severity of the in-fections and in the short-term outcomes. Ultimately, we analysed the RSV prevalence in the global bronchiolitis hospitalization in the same over reported periods. Overall, we included 237 patients. Before the Pandemic, the peak was recorded in January and February while after the Pandemic, the peak was in November and December. A higher prevalence of RSV was demon-strated after the Pandemic compared to the period before the Pandemic; no difference in severity was reported overall. In conclusion, an increase in RSV cases after the Pandemic has been demonstrated with an anticipated peak, while no differences were recorded in severity.