Abstract
Objectives Respiratory syncytial virus (RSV) represents a significant clinical and economic burden among older adults, being associated with high hospitalization rates and substantial healthcare costs. The recent development of RSV vaccines offers an opportunity to adopt preventive strategies targeting this vulnerable population. Implementing this solution could reduce the morbidity and mortality associated with this infection. The aim of this study is to assess the efficiency of vaccination against RSV infection in adult patients aged 75 or above in Spain. Methods A decision tree economic model was developed to compare RSV vaccination with non-vaccination in a Spanish population aged >=75, from the payer's perspective (Spanish National Health System) and a two-year time horizon. Epidemiological and vaccine efficacy data obtained from a systematic literature review were employed, alongside healthcare costs extracted from official sources. Health outcomes were estimated in quality-adjusted life years (QALYs). Deterministic and probabilistic sensitivity analyses were performed to assess the model uncertainty. Results In adults aged >=75, RSV vaccination showed an incremental cost of 100.25 and an incremental QALY of 0.003146, with an incremental cost-utility ratio (ICUR) of 31,868.69/QALY. The deterministic sensitivity analysis identified the vaccine price as the main driver of efficiency, only being cost-effective below 111.19. In the probabilistic analysis, the cost-utility probability at the 25,000/QALY threshold stood at 19.72%. Conclusion From the perspective of the Spanish National Health Service and with a 2-year horizon, vaccinating against RSV in adults aged >=75 is not cost-effective at a willingness-to-pay threshold of 25,000/QALY. Efficiency is mainly conditioned by price; scenarios with lower prices and, to a lesser extent higher incidence, coverage or vaccine efficacy would improve its economic viability in Spain.Copyright © 2026 The Authors.
