Cost-effectiveness of vaccination of older adults with an MF59®-adjuvanted quadrivalent influenza vaccine compared to standard-dose and high-dose vaccines in South Korea and Taiwan

Influenza carries a high risk of severe complications and mortality among individuals aged ≥65 years. Advanced influenza vaccines, such as MF59®-adjuvanted influenza vaccine (aQIV) and high-dose influenza vaccine (HD-QIV), offer enhanced protection for older adults compared to standard-dose vaccines (SD-QIV). This study evaluated the cost-effectiveness of vaccination strategies using aQIV compared to SD-QIV and HD-QIV in South Korea and Taiwan for individuals ≥65 years from healthcare payer and societal perspectives, using a static decision tree model to estimate economic and clinical outcomes. Compared to SD-QIV, aQIV was estimated to prevent an additional 71,352 and 13,530 symptomatic influenza infections, 5,443 and 819 hospitalizations due to influenza-related complications, and 1,275 and 140 deaths per influenza season in South Korea and Taiwan, respectively. From a healthcare payer perspective, the incremental cost per quality-adjusted life year (QALY) gained with aQIV versus SD-QIV was 2,200 USD per QALY in South Korea and 6,798 USD per QALY in Taiwan, both of which fall below the respective willingness-to-pay thresholds in these countries based on the vaccine price ratios and relative vaccine effectiveness estimates incorporated in the model. Under the same parameters, and assuming both vaccines were available, aQIV was found to be a cost-saving strategy compared to HD-QIV in both countries from payer and societal perspectives. As official price data for HD-QIV and aQIV were not publicly available, expert-informed estimates were applied, which may introduce residual uncertainty. Our results imply that introducing aQIV for the ≥65 population might significantly reduce the clinical and economic burden of influenza in these countries. These findings support the benefits of aQIV as an enhanced influenza vaccine in national immunization programs targeting ≥65 year olds.