Economic evaluation of the second booster dose of diphtheria-tetanus-acellular pertussis vaccine for children aged 6 years in Zhejiang Province: A cost-utility analysis.

Despite increasing pertussis breakthroughs and waning immunity, this study evaluates the cost-effectiveness of replacing the DT booster with DTaP in 6-year-olds in Zhejiang, China. While implemented in high-income regions, this strategy's cost-effectiveness remains unassessed in diverse Chinese settings. We address this gap using local data.Using surveillance data from the Zhejiang Provincial Center for Disease Control and Prevention, literature reviews, and a 10-year simulation timeframe, a decision tree-Markov model was constructed from a societal perspective. The study cohort was 6-year-old children in Zhejiang Province in 2022. Comprehensive evaluation indicators, including Incremental Cost Effectiveness Ratio (ICER) and Incremental Cost-Utility Ratio (ICUR), were used. Robustness was assessed via Deterministic Sensitivity Analysis (DSA) and Probabilistic Sensitivity Analysis (PSA). Simulating 10 years after implementing the DTaP strategy for 628,619 children in 2022, under lower background incidence, DTaP could prevent 1,886 pertussis cases, reduce costs by 1.7 billion CNY, and gain 0.09 QALYs (ICUR = 3,096.15 CNY/QALY). Under higher incidence, it could prevent 8,743 cases, reduce costs by 1.6 billion CNY, and gain 0.084 QALYs (ICUR = 3,081.86 CNY/QALY). Both ICUR values are significantly lower than Zhejiang's per capita GDP (118,496 CNY). Our findings indicate that administering a second booster dose of DTaP to 6-year-old children is cost-effective, particularly with high incidence of pertussis.