Health and economic impact of the 21-valent pneumococcal conjugate vaccine (V116) for adults in Japan: a delta price approach

This study analyzed the health and economic impact of the 21-valent pneumococcal conjugate vaccine (V116) and the 20-valent pneumococcal conjugate vaccine (PCV20), as well as their relative cost-effectiveness, in Japanese adults aged 65 years using a delta pricing approach. A Markov model was employed to simulate the movement of the Japanese population among four health states: healthy, pneumococcal disease (consisting of invasive pneumococcal disease [IPD] with or without meningitis and non-bacteremic pneumococcal pneumonia [NBPP]), post-meningitis sequelae, and death. The model was populated with publicly available demographic and epidemiologic data, stratified by risk level. Pneumococcal serotype distribution and vaccine effectiveness, as well as direct and indirect treatment costs and health-related utilities, were derived from published sources. The model used a lifetime horizon and 2% discounting of costs and life-years. Costs were adjusted to 2023 values in Japanese yen (¥). Outcomes were cases and deaths, life-years and quality-adjusted life-years (QALYs), vaccination and treatment costs, and incremental cost-effectiveness ratios. The range over which V116 was cost-saving and cost-effective was determined. Compared to PCV20, V116 averted an additional 28 cases of IPD, 918 cases of NBPP, 5 deaths from IPD, and 51 deaths from NBPP over the lifetime of a single age 65 cohort. Life-years and QALYs gained were 1,019 and 642, respectively, relative to PCV20; V116 saved ¥733 million in direct medical costs and ¥557 million in indirect costs, compared to PCV20. V116 was found to be cost-saving at price premiums up to ¥1,322 (payer perspective) or ¥2,327 (societal perspective) and remained below a willingness-to-pay threshold of ¥5 million/QALY for premiums up to ¥7,113 (payer perspective) or ¥8,117 (societal perspective). V116 is projected to provide more population health benefits in Japan than PCV20, and to be cost-effective at a variety of price premiums. The burden of pneumococcal disease in Japan is substantial. The publicly funded immunization program in Japan currently includes a 13-valent pneumococcal conjugate vaccine (PCV13) for children <5 years and a 23-valent pneumococcal polysaccharide vaccine (PPSV23) for adults aged ≥65 years and for adults aged 60–64 years with certain chronic medical or immunocompromising conditions. However, the prevalence of pneumococcal disease due to serotypes not present in PCV13 or PPSV23 is rising. The present study assessed the health and economic impact of higher-valency vaccines including the 21-valent pneumococcal conjugate vaccine (V116) and the 20-valent pneumococcal conjugate vaccine (PCV20) at the population level as well as their relative cost-effectiveness, in Japanese adults. For the current Japanese 65-year-old population, our model predicted better health and economic outcomes with a V116 vaccination program compared to a PCV20 vaccination program. Across all age groups, V116 averted more pneumococcal disease cases and deaths than PCV20 and increased the life-years gained. V116 remained cost-effective at a variety of price premiums and became cost-saving at lower premiums. The results of this and other cost-effectiveness analyses will guide decision-makers in Japan regarding which vaccines will be used in the adult national immunization program.