Cost-effectiveness of respiratory syncytial virus vaccination strategies for older Canadian adults: a multi-model comparison

Abstract

Background: Two respiratory syncytial virus (RSV) vaccines are currently approved for use in adults aged 60 years and older in Canada. Economic analyses have shown that adult RSV vaccination programs may be cost-effective, particularly when focused on people at increased risk of RSV disease due to increased age or presence of chronic medical conditions (CMCs). We conducted a multi-model comparison to explore the impact of alternate model structural and methodological assumptions on the cost-effectiveness of RSV vaccination programs. Methods: We compared three static cost-utility models developed by the Public Health Agency of Canada, GSK, and Pfizer using a common set of input parameters. Each model evaluated sequential incremental cost-effectiveness ratios (ICERs) in 2023 Canadian dollars per quality-adjusted life year (QALY) for a set of policy alternatives, with vaccine eligibility determined by combinations of age and CMC status. Results were calculated for each vaccine separately for scenarios assuming two or three years of vaccine protection using the health system perspective and a 1.5% annual discount rate. Results: The three cost-utility models were broadly concordant across the scenarios modeled. In all scenarios, focusing on vaccination of people with CMCs was preferred over broader age-based policies. RSV vaccination for people with CMCs over the age of 70 years was most commonly identified as the optimal policy when using a cost-effectiveness threshold of $50,000/QALY. When only considering policies based on age criteria, vaccinating people over 80 years was cost-effective at this threshold. Discussion: A multi-model comparison of Canadian cost-utility models shows that RSV vaccination programs for RSV are likely cost-effective for some groups of older adults in Canada. These findings were consistent across models, despite differences in model structure.