BACKGROUND: Herpes zoster (HZ) and its complications significantly burden the Canadian healthcare system. Public health impact (PHI) and cost-utility of RZV in Canadians aged ≥50 was previously estimated in 2017 from available clinical trial data. We aim to update previously published estimates with recent long-term RZV efficacy and waning, real-world coverage and compliance data.
METHODS: A multi-cohort Markov model was used to conduct a cost-utility analysis (CUA) comparing RZV with no vaccination (cohort n= 14,819,192). Real-world data were applied to coverage (17.5%) and second dose completion rates (65%), as well as cost and demographics data. Incremental costs and benefits were calculated using a lifetime horizon from the healthcare payer perspective. A discount rate of 1.5% was applied to costs and quality-adjusted life years. Base-case, deterministic and scenario analyses were conducted.
RESULTS: RZV would prevent 304,000 HZ and 83,000 post-herpetic neuralgia (PHN) cases in the base case scenario. The incremental cost-effectiveness ratio (ICER) was CA$27,486. The number needed to vaccinate to prevent one HZ and PHN case was 9 and 32, respectively. Deterministic sensitivity analyses showed that results were most sensitive to PHN incidence amongst HZ cases and QALY losses due to PHN. First-dose coverage assumption of 80% reduced HZ and PHN cases by an additional 1,085,000 and 297,000, respectively.
CONCLUSIONS: RZV reduced public health burden and remains a cost-effective option for prevention of HZ assuming a willingness-to-pay threshold of CA$50,000.
