Cost-Effectiveness Analysis of Recombinant Zoster Vaccine at Age 50 for Chinese Adults with Mild Cognitive Impairment: A Modelling Study

Background: The recombinant zoster vaccine (RZV) has been shown to reduce the risk of dementia and delay cognitive decline. However, economic evaluations in populations with mild cognitive impairment (MCI), particularly those incorporating cognitive outcomes, remain unavailable. This study evaluated the cost-effectiveness of RZV vaccination at age 50 among Chinese adults with MCI. Methods: A decision tree–Markov model was developed from a societal perspective to assess the lifetime cost-effectiveness of RZV (Shingrix, GSK) in a cohort of 1 million immunocompetent Chinese adults with MCI receiving vaccination at the age of 50. The primary outcome was the incremental cost-effectiveness ratio (ICER), while secondary outcomes included cases averted and the number needed to vaccinate (NNV) to prevent one case of herpes zoster (HZ), postherpetic neuralgia (PHN), and dementia. A willingness-to-pay (WTP) threshold equivalent to the 2024 Chinese gross domestic product (GDP) per capita (13,121 USD) was applied. Sensitivity analyses were conducted to test the robustness of the results. Results: Over a lifetime horizon, RZV vaccination was estimated to avert 54.64% of HZ cases, 97.58% of PHN cases, and 12.28% of dementia cases compared with no vaccination, resulting in an additional 2.23 million quality-adjusted life years (QALYs) gained. The ICER was 4216.99 USD/QALY, remaining well below the WTP threshold. The corresponding NNVs were 6.25 for HZ, 24.03 for PHN, and 280.82 for dementia progression. Conclusions: RZV vaccination is cost-effective for Chinese adults aged 50 years with MCI, providing substantial health gains through reductions in both HZ burden and dementia progression.