Transitioning to routine immunization: Cost-effectiveness of a national COVID-19 vaccination program for older adults...

COVID-19 continues to evolve, yet it remains excluded from South Korea's National Immunization Program (NIP). This study assesses the cost-effectiveness of introducing COVID-19 vaccination into the NIP for older adults.

A static decision-tree model was employed from a societal perspective to compare a single-dose NIP strategy against no vaccination for adults aged ≥65. Model inputs were derived from real-world data, assuming a 2-year average incidence and 6-month vaccine protection duration. Sensitivity and scenario analyses, including a budget impact analysis for 2025-2029, were performed.

The NIP strategy was estimated to prevent 3,011 deaths and 22,031 hospitalizations. The base-case incremental cost-effectiveness ratio (ICER) was KRW 9.17 million per quality-adjusted life year (QALY) gained, significantly below the willingness-to-pay threshold. ICERs remained robust across scenarios, ranging from KRW 3.44 million to 34.79 million. Targeting adults aged ≥75 further improved the ICER to KRW 2.94 million/QALY. Results were generally robust across sensitivity analyses, although epidemiology remained a key determinant. The annual budget impact was projected to reach KRW 581.9 billion by 2029 at 50% coverage.

Introducing COVID-19 vaccination into the NIP for older adults is cost-effective. These findings provide a robust evidence base for long-term immunization planning in Korea and similar global contexts.