Evaluation of the cost-effectiveness in the United States of a vaccine to prevent herpes zoster and postherpetic neuralgia in older adults

Context: A live-attenuated varicella-zoster virus vaccine, demonstrated to reduce the incidence of herpes zoster (HZ) and postherpetic neuralgia (PHN) and the morbidity associated with incident HZ and its sequelae, has recently been approved for use in the United States (U.S.). Objective: To examine the potential value of zoster vaccine for society and payers. Design, setting and population: An age-specific decision analytic model was designed to estimate the lifetime costs and outcomes associated with HZ, PHN and other HZ-related complications for vaccinated and non-vaccinated cohorts aged >= 60 years. Clinical trial data, published literature and other primary studies were used to inform the model. Robustness of results to key model parameters was explored through a series of one-way, multivariate and probabilistic sensitivity analyses. Both societal and payer perspectives were considered. Main outcome measure: Incremental cost per quality-adjusted life year (QALY) gained. Results: For a representative cohort of 1,000,000 U.S. vaccine recipients aged >= 60 years, use of the zoster vaccine was projected to eliminate 75,548-88,928 HZ cases and over 20,000 PHN cases. Over 300,000 outpatient visits, 375,000 prescriptions, 9700 ER visits and 10,000 hospitalizations were projected to be eliminated with the vaccine translating into savings of US$ 82 million to US$ 103 million in healthcare costs associated with the diagnosis and treatment of HZ, PHN and other HZ-related complications. Cost-effectiveness ratios range from US$ 16,229 to US$ 27,609 per QALY gained, depending on the input data source and analytic perspective. Results were most sensitive to PHN costs, duration of vaccine efficacy, vaccine efficacy against PHN and HZ, QALY loss associated with pain states and complication costs. Conclusions: The zoster vaccine at a price of US$ 150 is likely to be cost-effective for a cohort of immunocompetent U.S. vaccine recipients aged >= 60 years using commonly cited thresholds for judging cost-effectiveness. Conclusions are robust over plausible ranges of input parameter values and a broad range of scenarios and age cohorts. (C) 2007 Elsevier Ltd. All rights reserved.