LAUSR

ABSTRACT Background Respiratory infections like pneumococcal disease (PD), respiratory syncytial virus (RSV), influenza (Flu), and COVID-19 significantly impact Japan’s aging population, imposing substantial health and economic burdens. Effective vaccines exist, yet uptake remains limited due to funding constraints and vaccine hesitancy. This study assessed the societal return on investment in adult respiratory vaccination programs to support informed policy decisions. Research design & methods We conducted a benefit-cost analysis using static cohort models and life tables to estimate benefit-cost ratios (BCRs) and societal net benefits (NBs), monetizing health impacts through the value of statistical life and cost-of-illness methods. Costs comprised vaccination program expenses. Scenario and sensitivity analyses explore coverage scenarios and parameter assumptions. Results Adult vaccination programs generated BCRs around 18:1 within 5 years and 20:1 over a lifetime. Lifetime NBs exceeded ¥113 trillion, preventing nearly three million hospitalizations and freeing millions of hospital bed-days, alongside avoiding over ¥100 billion in productivity losses. Expanding vaccine coverage significantly increased the NBs by > 30%, whereas reduced COVID-19 vaccine uptake notably diminished returns. Conclusion Japan’s adult respiratory vaccination programs generate substantial socioeconomic returns, strengthening public health, healthcare resilience, and workforce productivity. Increasing uptake across the population can generate significantly higher NBs. Realizing these benefits requires addressing vaccine uptake barriers and enhancing public investment.