Abstract
INTRODUCTION: This study aimed to update cost-effectiveness and public health impact estimates of the two-dose recombinant zoster vaccine (RZV) compared with no vaccination against herpes zoster (HZ) in the Japanese population aged 65 years. List price of the vaccine and latest RZV efficacy and waning estimates were incorporated. METHODS: A multicohort static Markov model with a cycle length of 1 year was used to follow a hypothetical cohort of one million people aged 65 years over their remaining lifetime (base case). Age-stratified vaccine efficacy and waning rates were updated on the basis of the latest clinical trial data (interim ZOE-LTFU; NCT02723773). First-dose coverage was assumed at 40%, and second-dose compliance was assumed at 95%. Costs and outcomes were discounted at 2% annually, and the incremental cost-effectiveness ratio (ICER) was calculated from payer and societal perspectives. The societal perspective considered productivity loss due to suffering HZ, or due to suffering HZ and time required for vaccination. Sensitivity analyses explored the overall uncertainties in the model. Scenario analyses for Japanese adults aged 50, 60, 70, 80, ≥ 50, and ≥ 65 years (main scenario) were conducted. An ICER below ¥5-6 million/quality-adjusted life-year (QALY) was considered cost-effective. RESULTS: RZV was estimated to prevent 71,423 HZ cases and 15,858 post-herpetic neuralgia (PHN) cases per million people aged 65 years compared with no vaccine in Japan. The ICER was ¥4,205,515 from a payer perspective and was most sensitive to assumptions regarding vaccine efficacy waning, proportion of patients with HZ developing PHN, and HZ incidence. From societal perspectives, ICERs were ¥3,854,192 (productivity loss from suffering HZ only) and ¥4,622,212 (productivity loss from suffering HZ and time required for vaccination). Overall, the results were considered robust under extensive sensitivity and scenario analyses. CONCLUSION: Vaccination against HZ with RZV is cost-effective compared with no vaccination in Japanese adults aged 65 years.