Estimated impact of nirsevimab prophylaxis on the economic burden of respiratory syncytial virus disease in Northern Italy

Background: Respiratory syncytial virus (RSV) is a frequent cause of acute lower respiratory tract infection (LRTI) in infants; however, the health and economic burden of infant RSV-associated LRTI in Northern Italy has not been sufficiently assessed. We evaluated the clinical and economic burden of RSV-associated LRTI requiring emergency department (ED) access and/or hospitalization in infants less than 6 months old in two provinces in Northern Italy and estimated the potential impact of universal immunization with a recently approved monoclonal antibody. Methods: Epidemiological data during the 2021–2022 and 2022–2023 RSV seasons were obtained from administrative records and anonymized to comply with confidentiality requirements. Resource utilization was estimated using the costs associated with each event, obtained from the available literature and an analysis of national hospital discharge records. A static decision analytic model was used to estimate RSV-related health and associated cost outcomes. Results: Overall, 882 ED accesses and 430 hospital admissions associated with RSV were recorded during two consecutive epidemic seasons. Intensive care admission was needed in 85 cases. Universal immunization would avoid 406 ED accesses and 199 hospital admissions. The total economic burden was estimated at over €1.5 million, of which 51% was for hospitalization, 20% for intensive care, and 9% for ED access. An additional 10% was estimated for the management of long-term consequences of RSV-associated LRTI. Universal immunization would avoid expenses of €124,092 for ED accesses and €999,629 for hospital admissions. Conclusions: These findings underscore the substantial health and economic burden of RSV disease, highlighting the potential benefits of universal prevention strategies, while informing policymaker decisions regarding implementation of immunoprophylaxis.