Respiratory syncytial virus vaccination strategies for older Canadian adults: a cost-utility analysis

Background: Vaccines against respiratory syncytial virus (RSV) have the potential to reduce disease burden and costs in Canadians, but the cost-effectiveness of RSV vaccination programs for older adults is unknown. We evaluated the cost-effectiveness of different adult age cutoffs for RSV vaccination programs, with or without a focus on people with higher disease risk due to chronic medical conditions (CMCs). Methods: We developed a static individual-based model of medically-attended RSV disease to evaluate the cost-utility of alternate age-, medical risk-, and age- plus medical risk-based vaccination policies. The model followed a multi-age cohort of 100,000 people aged 50 years and older over a three-year period. Vaccine characteristics were based on RSV vaccines authorized in Canada as of March 2024. We calculated incremental cost-effectiveness ratios (ICERs) in 2023 Canadian dollars per quality-adjust life year (QALY) from the health system and societal perspectives, discounted at 1.5%. Results: Although all vaccination strategies averted medically-attended RSV disease, strategies focused on adults with CMCs were more likely to be cost-effective than age-based strategies. A program focused on vaccinating adults aged 70 years and older with one or more CMCs was optimal for a cost-effectiveness threshold of $50,000 per QALY. Results were sensitive to assumptions about vaccine price, but approaches based on medical risk remained optimal compared to age-based strategies even when vaccine prices were low. Findings were robust to a range of alternate assumptions. Interpretation: Based on available data, RSV vaccination programs in some groups of older Canadians with underlying medical conditions are expected to be cost-effective. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript