COST-EFFECTIVENESS OF HIGH-DOSE INFLUENZA VACCINE STRATEGIES FOR OLDER ADULTS IN JAPAN
Author(s)
Shunya Ikeda, MD, PhD1, Mia Kobayashi, PhD2, Yuriko Hagiwara, PhD3, Ayako Shoji, PhD3, Hiroshi Yoshihara, MS3, Ataru Igarashi, PhD3.
1International University of Health and Welfare/Keio University, Tokyo, Japan, 2Yamanashi University, Chuo-shi, Japan, 3Keio University, Tokyo, Japan.
1International University of Health and Welfare/Keio University, Tokyo, Japan, 2Yamanashi University, Chuo-shi, Japan, 3Keio University, Tokyo, Japan.
OBJECTIVES: Seasonal influenza causes substantial morbidity and mortality among older adults. A high-dose inactivated influenza vaccine has shown greater immunogenicity and effectiveness than standard-dose vaccine, but its economic value in Japan remains uncertain. We evaluated age-targeted introduction strategies using a high-dose vaccine price of JPY 5,000 and a JPY 5 million/QALY threshold.
METHODS: A cost-utility model was applied to adults aged ≥65 years from the healthcare payer perspective. Strategies included no vaccination, standard-dose vaccination for all eligible adults, and replacing standard-dose vaccine with high-dose vaccine for adults aged ≥65, ≥70, ≥75, or ≥80 years while maintaining standard-dose vaccination below each threshold. We assumed one-season vaccine protection, lifetime mortality loss, standard-dose vaccine price JPY 1,500, administration cost JPY 3,200, and 100% high-dose uptake among eligible age groups. Outcomes were costs, QALYs, and ICERs. Vaccine effects were applied to influenza illness and hospitalization; scenario analyses included related respiratory and cardiovascular disease prevention.
RESULTS: Current standard-dose vaccination cost JPY 6,403, produced 0.95936 QALYs, and had an ICER of JPY 1.935 million/QALY versus no vaccination. Introducing high-dose vaccine for all adults aged ≥65 years increased QALYs to 0.96005 and yielded ICERs of JPY 2.639 million/QALY versus no vaccination and JPY 4.709 million/QALY versus standard dose. Age-targeted high-dose introduction for ≥70, ≥75, and ≥80 years had ICERs versus standard dose of JPY 4.043, 3.576, and 5.570 million/QALY, respectively. The ≥75-year strategy had the most favorable ICER, costing JPY 8,270 and producing 0.95988 QALYs. Scenario analyses incorporating related diseases further improved cost-effectiveness and showed dominance in best-case assumptions.
CONCLUSIONS: At JPY 5,000 per high-dose vaccine dose, introducing high-dose influenza vaccine for adults aged ≥65, ≥70, or ≥75 years was cost-effective versus standard dose. Targeting adults aged ≥75 years provided the most efficient use of resources among evaluated strategies. These findings may inform age prioritization within Japan's existing influenza vaccination program.
METHODS: A cost-utility model was applied to adults aged ≥65 years from the healthcare payer perspective. Strategies included no vaccination, standard-dose vaccination for all eligible adults, and replacing standard-dose vaccine with high-dose vaccine for adults aged ≥65, ≥70, ≥75, or ≥80 years while maintaining standard-dose vaccination below each threshold. We assumed one-season vaccine protection, lifetime mortality loss, standard-dose vaccine price JPY 1,500, administration cost JPY 3,200, and 100% high-dose uptake among eligible age groups. Outcomes were costs, QALYs, and ICERs. Vaccine effects were applied to influenza illness and hospitalization; scenario analyses included related respiratory and cardiovascular disease prevention.
RESULTS: Current standard-dose vaccination cost JPY 6,403, produced 0.95936 QALYs, and had an ICER of JPY 1.935 million/QALY versus no vaccination. Introducing high-dose vaccine for all adults aged ≥65 years increased QALYs to 0.96005 and yielded ICERs of JPY 2.639 million/QALY versus no vaccination and JPY 4.709 million/QALY versus standard dose. Age-targeted high-dose introduction for ≥70, ≥75, and ≥80 years had ICERs versus standard dose of JPY 4.043, 3.576, and 5.570 million/QALY, respectively. The ≥75-year strategy had the most favorable ICER, costing JPY 8,270 and producing 0.95988 QALYs. Scenario analyses incorporating related diseases further improved cost-effectiveness and showed dominance in best-case assumptions.
CONCLUSIONS: At JPY 5,000 per high-dose vaccine dose, introducing high-dose influenza vaccine for adults aged ≥65, ≥70, or ≥75 years was cost-effective versus standard dose. Targeting adults aged ≥75 years provided the most efficient use of resources among evaluated strategies. These findings may inform age prioritization within Japan's existing influenza vaccination program.
Conference/Value in Health Info
2026-09, ISPOR Asia Pacific 2026, Bangkok, Thailand
Value in Health, Volume 55, Issue S1
Code
EE112
Topic
Economic Evaluation
Disease
STA: Vaccines