Determining the Optimal Vaccination Schedule for Herpes Zoster: a Cost-Effectiveness Analysis.

BACKGROUND: The Advisory Committee on Immunization Practices recommends a single dose of herpes zoster (HZ) vaccine in persons aged 60 years or older, but the efficacy decreases to zero after approximately 10 years. A booster dose administered after 10 years might extend protection, but the cost-effectiveness of a booster strategy has not been examined.

OBJECTIVE: We aimed to determine the optimal schedule for HZ vaccine DESIGN: We built a Markov model to follow patients over their lifetime. From the societal perspective, we compared costs and quality-adjusted life years (QALYs) saved of 11 strategies to start and repeat HZ vaccine at different ages.

SUBJECTS: Adults aged 60 years.

INTERVENTION: HZ vaccine.

MAIN MEASURES: Costs, quality-adjusted life years (QALYs), and incremental costs per QALY saved.

KEY RESULTS: At a $100,000/QALY threshold, "vaccination at 70 plus one booster" was the most cost-effective strategy, with an incremental cost-effectiveness ratio (ICER) of $36,648/QALY. "Vaccination at 60 plus two boosters" was more effective, but had an ICER of $153,734/QALY. In deterministic sensitivity analysis, "vaccination at 60 plus two boosters" cost < $100,000/QALY if compliance rate was > 67 % or vaccine cost was < $156 per dose. In probabilistic sensitivity analysis, "vaccination at 70 plus one booster" was preferred at a willingness-to-pay of up to $135,000/QALY.

CONCLUSIONS: Under current assumptions, initiating HZ vaccine at age 70 years with one booster dose 10 years later appears optimal. Future data regarding compliance with or efficacy of a booster could affect these conclusions.