When Cost-Effectiveness Crosses Borders—Nirsevimab as an Example

Real-world evidence is increasingly used for immunization policy and resource allocation decisions, and in this issue of JAMA Pediatrics, Attaianese et al demonstrate potentially high economic favorability for nirsevimab immunization to prevent respiratory syncytial virus (RSV) under a wide range of conditions in Italy. Using Poisson regression models based on 2 seasons of data from hospitals representing differential catchment areas, they estimate RSV infections that would have occurred in the 2024 to 2025 RSV season and compare them with actual infections observed.

Although there is inherent uncertainty comparing a model-based estimate with observed infections, Attaianese et al find nirsevimab to be cost saving, and the study serves as an example of the value of immunization in preventing illness, saving lives, and saving money. Beyond its country-specific findings, this study underscores the critical influence of health system characteristics on the economic favorability of the same intervention across countries.