Cost-Effectiveness of a Vaccine to Prevent Herpes Zoster and Postherpetic Neuralgia in Older Adults

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Abstract
Background.A vaccine to prevent herpes zoster was recently approved by the United States Food and Drug Administration. We sought to determine the cost-effectiveness of this vaccine for different age groups. Methods.We constructed a cost-effectiveness model, based on the Shingles Prevention Study, to compare varicella zoster vaccination with usual care for healthy adults aged >60 years. Outcomes included cost in 2005 US dollars and quality-adjusted life expectancy. Costs and natural history data were drawn from the published literature; vaccine efficacy was assumed to persist for 10 years. Results.For the base case analysis, compared with usual care, vaccination increased quality-adjusted life expectancy by 0.0007–0.0024 quality-adjusted life years per person, depending on age at vaccination and sex. These increases came almost exclusively as a result of prevention of acute pain associated with herpes zoster and postherpetic neuralgia. Vaccination also increased costs by $94–$135 per person, compared with no vaccination. The incremental cost-effectiveness ranged from $44,000 per quality-adjusted life year saved for a 70-year-old woman to $191,000 per quality-adjusted life year saved for an 80-year-old man. For the sensitivity analysis, the decision was most sensitive to vaccine cost. At a cost of $46 per dose, vaccination cost <$50,000 per quality-adjusted life year saved for all adults >60 years of age. Other variables related to the vaccine (duration, efficacy, and adverse effects), postherpetic neuralgia (incidence, duration, and utility), herpes zoster (incidence and severity), and the discount rate all affected the cost-effectiveness ratio by >20%. Conclusions.The cost-effectiveness of the varicella zoster vaccine varies substantially with patient age and often exceeds $100,000 per quality-adjusted life year saved. Age should be considered in vaccine recommendations.