Cost-effectiveness Analysis of High-Dose Trivalent Influenza Vaccine in Adults Aged 65 Years and Older in Korea

Background:As Korea transitions into a super-aged society, preventing influenza and its complications in older adults is essential to reduce morbidity, mortality, and healthcare costs.This study evaluated the cost-effectiveness of high-dose trivalent influenza vaccine (HD-TIV) versus MF59-adjuvanted trivalent influenza vaccine (aTIV) in adults aged 65 years, in line with updated WHO recommendations.Methods: A decision-tree model was developed from the Korean healthcare payer perspective to compare HD-TIVs and aTIVs under two scenarios: respiratory events and cardio-respiratory events.Relative vaccine effectiveness (rVE) was derived from randomized controlled trials comparing each vaccine with standard-dose TIVs.The model estimated lifetime direct medical costs, quality-adjusted life years (QALYs), and life years (LYs).Deterministic (DSA) and probabilistic sensitivity analyses (PSA) were performed to assess uncertainty.Results: HD-TIV was cost-effective across all scenarios and age groups.In adults aged 65 years, the ICER for the cardio-respiratory scenario was KRW 5.42 million per QALY, well below willingness-to-pay thresholds.Assuming an aTIV price of KRW 30,000, the cost-effective ceiling price for HD-TIV exceeded twice that of aTIV.Among those aged 75 years, higher efficacy of HD-TIV (rVE 32.4%) translated into 14,760 fewer hospitalizations, with an ICER of KRW 1.47 million per QALY, confirming robust cost-effectiveness even at prices up to approximately seven times that of aTIV.Conclusions: HD-TIV demonstrates consistent cost-effectiveness compared with aTIV in Korean older adults and may improve individual outcomes while reducing healthcare utilization and alleviating the broader public health and economic burden of influenza.