Cost-benefit analysis of nirsevimab for respiratory syncytial virus prevention in infants: a population-based study.

Respiratory syncytial virus (RSV) represents a major healthcare, economic, and social burden, particularly among infants. The present study aims to evaluate, from a public health perspective, the economic impact of implementing a universal immunization strategy with nirsevimab in the Community of Madrid (CM).A cost-benefit analysis was conducted from both healthcare and societal perspectives using real-world observational data. The study included all newborns between April 1 and December 31, 2023. The follow-up period corresponded to the RSV epidemic season (October 2023-March 2024). Data sources included administrative, clinical, vaccination, and epidemiological surveillance records. Direct costs included primary care, emergency services, and hospitalizations-with and without intensive care-while indirect costs captured parental productivity losses. A probabilistic model with Monte Carlo simulations (100,000 iterations) was used to assess uncertainty, and the internal rate of return (IRR) was calculated for different dose price scenarios. The study included 37,689 newborns. The incidence density of healthcare events was consistently lower among immunized children. The IRR was 62% at a price of €209 per dose, remaining positive up to €330 per dose. At the base price (€209 per dose), the intervention was cost-beneficial in 100% of simulations. Universal immunization with nirsevimab in the CM proved to be cost-beneficial and robust across various price scenarios, supporting its inclusion in child public health programs. Conclusion: Universal immunization with nirsevimab in the CM proved to be cost-beneficial and robust across various price scenarios, supporting its inclusion in child public health programs. What is known: • Respiratory syncytial virus (RSV) causes a major clinical and economic burden in infants due to high hospitalization and emergency care rates during seasonal epidemics. • Clinical trials and modeling studies suggest that nirsevimab effectively prevents RSV disease and may be economically favorable, but real-world cost-benefit evidence remains limited. What is new: • This study presents a real-world, population-based cost-benefit analysis of a universal nirsevimab immunization campaign using administrative and clinical data from a regional birth cohort. • Universal immunization was cost-beneficial from both healthcare and societal perspectives across a wide range of price scenarios, demonstrating robust economic returns under real-life conditions.