Herpes Zoster vaccination coverage and its determinants in older adults: A Meta-analysis.

BACKGROUND: Herpes zoster is associated with morbidity in older adults and immunocompromised individuals. Despite the availability of effective vaccines, vaccination uptake remains poorly quantified and heterogeneous across countries. OBJECTIVES: To estimate herpes zoster vaccination coverage among individuals for whom vaccination is recommended based on age in their respective countries, and to identify factors associated with vaccine uptake and temporal trends. METHODS: Data sources: MEDLINE, CENTRAL, Web of Science, CINAHL, Google Scholar, reference lists, and grey literature sources were searched through June 2025. STUDY ELIGIBILITY CRITERIA: Studies reporting herpes zoster vaccination coverage in age-eligible populations according to national or regional recommendations were included. PARTICIPANTS: Older adults eligible for herpes zoster vaccination based on age-based recommendations in their respective countries. INTERVENTIONS: No intervention effects were evaluated. Vaccination status under routine care was assessed. Assessment of risk of bias: Risk of bias was assessed using the Hoy et al. tool for prevalence studies. METHODS: of data synthesis: Vaccination coverage was pooled using a random-effects meta-analysis of proportions. Meta-regression and subgroup analyses explored determinants of uptake, including population characteristics, vaccine availability, reimbursement policies, and country-level indicators of vaccine confidence. RESULTS: Thirty-eight studies from 13 countries were included, covering data collected between 2007 and 2025. Herpes zoster vaccination coverage ranged from 0% to 53%. The pooled vaccination coverage across included countries was 14% (95% CI: 9-20%), with high heterogeneity. Higher uptake was associated with influenza and pneumococcal vaccination coverage, educational level, reimbursement policies, longer time since vaccine introduction, and greater public trust in vaccine effectiveness and scientific institutions. Herpes zoster vaccination coverage increased over time following vaccine implementation. CONCLUSIONS: Herpes zoster vaccination coverage remains low and highly unequal. Uptake is mainly driven by healthcare system organization and integration within adult immunization programs, highlighting the importance of structured vaccination policies to improve prevention worldwide.