米国65歳以上でワクチン接種経験のある成人におけるPCV21使用の費用対効果分析

In the United States (US), additional pneumococcal conjugate vaccine (PCV) with higher valency such as PCV21 is recommended for adults aged ≥65 years who have previously received pneumococcal vaccines (referred to as vaccine-experienced). This study assessed the cost-effectiveness of using PCV21 (compared to recommended options at the time-23-valent pneumococcal polysaccharide vaccine [PPSV23], PCV15, and PCV20) in adults aged ≥65 years who were previously vaccinated 5 years ago with PPSV23 or PCV13 or 2 years ago with PCV15.

A published static multi-cohort state-transition Markov model was used to estimate the lifetime clinical and economic outcomes of administering a single dose in vaccine-experienced adults from societal perspective. Quality-adjusted life years (QALYs) and costs (in 2023 USD) were discounted at an annual rate of 3%. Extensive deterministic sensitivity analysis (DSA), probabilistic sensitivity analyses (PSA), and scenario analysis with longer time since last vaccination were conducted to identify influential variables.

Compared with PPSV23, PCV21 in PCV13- and PCV15-experienced adults would cost $130,700 and $173,700 per QALY gained, respectively. Administering PCV21 in PPSV23-experienced adults would cost $2,700 compared with PCV15. PCV21 would be cost-saving compared with PCV20 in all vaccine-experienced adults. Discount rates and vaccine effectiveness were the most influential inputs as shown by the DSA results. The quantitative results were robust in PSA. When vaccine history was as long as 8 (instead of 5) years for the PPSV23-, PCV13-, or PPSV23+PCV13-experienced adults aged ≥65 years in the scenario analysis, the costs per QALY of PCV21 were slightly favorable in most comparisons.

In the US, a dose of PCV21 in adults aged ≥65 years who have previously received a pneumococcal vaccine has the potential to prevent a considerable number of pneumococcal disease cases and deaths while remaining economically reasonable over a wide range of inputs and scenarios.