BACKGROUND: Herpes Zoster (HZ) affects one in three adults in the United States (U.S.) over the course of their lifetimes. HZ is characterized by a highly painful rash and is associated with a substantial cost burden. One vaccine is currently marketed in the U.S. to prevent HZ, Zoster Vaccine Live (ZVL). A non-live adjuvanted subunit vaccine (HZ/su) for prevention of HZ is under regulatory review in the U.S.
OBJECTIVE: To determine the cost-effectiveness of HZ/su versus no vaccine and versus ZVL for U.S. adults not previously vaccinated against HZ aged 60+.
METHODS: The ZOster ecoNomic Analysis (ZONA) model is a deterministic Markov model. A hypothetical 1 million(M)-person cohort of U.S. adults not previously vaccinated against HZ aged 60+ was modeled over their remaining lifetimes from the year of vaccination with annual cycle lengths. Three different HZ vaccination strategies were compared: no vaccination, vaccination with HZ/su, and vaccination with ZVL. The primary perspective was societal, including both direct medical costs and indirect costs. Model inputs included: demographics, incidence and disease burden, vaccine characteristics, utilities, and vaccine costs. Costs and quality-adjusted life-years (QALYs) were presented over the lifetime of the cohort, with both discounted 3% per year. Deterministic and probabilistic sensitivity analyses, along with scenario and threshold analyses were carried out to explore the robustness of our findings considering uncertainty about model inputs.
RESULTS: The ZONA model estimated that in the 1M-person cohort, HZ/su vaccination would reduce disease burden resulting in a gain of 2,291 QALYs at a total societal cost of $27M compared to no vaccination. This produced an incremental cost-effectiveness ratio of $11,863 per QALY saved. Compared to ZVL, the ZONA model estimated that vaccination of the cohort with HZ/su would reduce disease burden and result in a gain of 1,261 discounted QALYs and societal cost savings of almost $96M. Sensitivity, scenario, and threshold analyses demonstrated robustness of these findings.
CONCLUSIONS: For vaccinating U.S. adults aged 60+ who have not been previously vaccinated against HZ, HZ/su is cost-effective relative to a no vaccination choice and cost saving relative to a vaccination with ZVL choice. These findings were robust as demonstrated by sensitivity, scenario, and threshold analyses.
