Economic and clinical burden associated with respiratory syncytial virus and impact of universal immunization with nirsevimab in Italy

Objectives: To describe the seasonal respiratory syncytial virus (RSV) burden in Italy considering the current prophylaxis strategy with palivizumab recommended only for high-risk infants (representing only 4.4% of an estimated birth cohort) and to evaluate the potential benefits of a new prophylaxis strategy targeting all infants with nirsevimab. Methods: A static decision analytic model previously used in the US was adapted to evaluate the RSV-related health and cost outcomes associated with nirsevimab versus standard of care (SoC) for the prevention of RSV medically attended lower respiratory tract infections (RSV-MA-LRTIs). Monthly probabilities of RSV infections, health events, mortality, and complications associated with RSV infections were obtained from the literature. Costs associated with each event were obtained using the available literature and through real-world data analy Results: For one RSV season, in the current SoC, the model estimated 216,100 RSV-MA-LRTIs, 15,121 associated complications, and 16 RSV-deaths-corresponding to an economic burden of approximately 50.5 million related to RSV-MA-LRTIs management, 10.9 million associated with potential complications due to RSV and 3 million in lost productivity due to RSV-deaths. Nirsevimab is expected to prevent 100,208 RSV-MA-LRTIs, 6,969 complications, and 6 deaths due to RSV infections, corresponding to an economic saving of about 23.3, 5, and 1.2 million, respectively. Conclusion: Nirsevimab is a new prophylaxis strategy that helps to protect all infants against RSV disease and could substantially reduce the clinical and economic burden of RSV in Italy in infants experiencing their first RSV season.