Cost-Effectiveness of Adjuvanted RSVPreF3 Vaccination for Adults Aged ≥60 Years in Colombia: Evidence to Inform National Immunization Policy

Background: Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults. This study assessed the cost-effectiveness of adjuvanted RSVPreF3 vaccination among adults aged ≥60 years. Methods: A static, multi-cohort Markov model with 1-month cycles and a 5-year horizon was developed in Microsoft Excel to simulate RSV-related outcomes from the societal perspective. The model incorporated seasonality, waning vaccine efficacy, and reinfection risk. Epidemiologic inputs were adapted from international data using Colombian adjustment factors. Vaccine efficacy over 30.6 months was modeled logarithmically from the AReSVi-006 trial and extrapolated to 5 years. Costs were derived from national cost-of-illness studies and expressed in 2025 USD, discounting costs and QALYs at 3%. Results: RSVPreF3 vaccination reduced RSV-related hospitalizations, deaths, and QALY losses. The base-case incremental cost-effectiveness ratio (ICER) was US $5,155 per QALY gained, marginally below Colombia’s willingness-to-pay threshold (US $5,180 per QALY). Subgroup analyses showed greater absolute health gains and lower ICERs in adults ≥65 years (US $2,990 per QALY). Probabilistic analysis confirmed cost-effectiveness in >95% of simulations; the vaccine remained cost-effective if priced ≤US $150 per dose. Conclusions: Adjuvanted RSVPreF3 vaccination is a cost-effective intervention for older adults in Colombia, offering substantial health and economic benefits under current national thresholds.