Cost-utility analysis of pre-exposure prophylaxis rabies vaccine in 5-year-old children in Thailand.

INTRODUCTION: Rabies remains a life-threatening disease affecting children in endemic regions including Thailand. The cost-effectiveness of pre-exposure prophylaxis (PrEP) rabies vaccination in the Thai context is unclear. This study analysed the cost-utility of adding PrEP rabies vaccination to post-exposure prophylaxis (PEP) rabies vaccination compared with PEP alone in 5-year-old children. METHODS: A decision tree model compared eight strategies (four PEP alone and four PrEP+PEP), classified by route of administration (intradermal (ID) or intramuscular (IM)) and vaccine product (purified chick embryo cell vaccine (PCEC) or chromatographically purified Vero cell vaccine (CPRV)/purified Vero cell rabies vaccine (PVRV)). Costs and outcomes were derived from published literature and discounted at 3% annually. The analysis was conducted from a societal perspective over a 20-year horizon. Incremental cost-effectiveness ratios (ICERs) were evaluated against Thailand's willingness-to-pay threshold of THB 160 000 per quality-adjusted life year (QALY). RESULTS: PrEP+PEP ID using PCEC was cost-effective, with an ICER of THB 40 977 (US$1160.8) per QALY versus PEP alone ID using PCEC; the remaining strategies were dominated. The one-way sensitivity analysis identified annual bite incidence as the most influential parameter, with the ICER ranging from cost-saving to not cost-effective (THB 454 265 (US$12 868.7) per QALY). The results were robust to variation in all other parameters. CONCLUSION: PrEP+PEP ID using PCEC is cost-effective for children in Thailand, reducing reliance on equine rabies immunoglobulin and disease-related QALY losses. These findings support integrating PrEP into Thailand's National Immunization Program for children in high-risk areas, prioritising early vaccination in high-risk populations to advance the goal of eliminating rabies by 2030.