Evaluating the socioeconomic value of adult respiratory immunization in Spain: a benefit-cost analysis

BACKGROUND: Vaccine-preventable illnesses, such as pneumococcal disease, respiratory syncytial virus, influenza, and COVID-19 place a significant burden on Spain's population health, health system, and economy. However, uptake and funding constraints limit the full value potential of Spain's national immunization programs. METHODS: A benefit - cost analysis was performed to assess the societal return on investment from adult vaccination by estimating benefit - cost ratios and net benefits (NBs). All outcomes were monetized using established methods. Program costs included all direct vaccination-related expenditures. Scenario and sensitivity analyses were performed to assess alternative program specifications and to test the robustness of the model. RESULTS: Spain's age-based respiratory immunization programs generate lifetime societal benefits of €1.9 when monetized mortality risk reduction is age-adjusted and €7.0 per €1 spent when monetized equally across all ages. This corresponds to NBs of €5.4 to €36.4 billion. Introducing adult RSV vaccination could increase NBs by up to 41%-21% compared to the status quo. Additionally, improving uptake across all programs would increase NBs by 134%-101%. CONCLUSIONS: Spain's adult respiratory vaccination programs generate positive socioeconomic returns. Including adult RSV vaccination and increasing vaccination uptake in general could further increase their societal benefits. Realizing these gains requires adequate public investment to improve vaccine uptake.