Herpes zoster vaccination and the risk of dementia: A systematic review and meta‐analysis
Sangam Shah, Krishna Dahal, Sangharsha Thapa, Prativa Subedi, Basanta Sharma Paudel, Swati Chand, Amr Salem, Markus Lammle, Ranjit Sah, Martin Kršák
Abstract
Abstract Introduction Previous studies have reported a decreased risk of dementia with herpes zoster vaccination. Given this background, this systematic review and meta‐analysis aimed to investigate the association between herpes zoster vaccination and the risk of dementia. Methods We searched five databases until November 2023 for case–control, cross‐sectional, or cohort studies investigating the association of herpes zoster vaccination and dementia. Odds ratios and 95% confidence intervals (95% CIs) were pooled in the meta‐analysis. Meta‐regression, subgroup, and sensitivity analysis were also conducted. Results We evaluated a total of five studies (one cross‐sectional, one case–control, and four cohort studies) that included a total number of 103,615 patients who were vaccinated with herpes zoster vaccine. All the studies were of high quality, ranging from 7 to 9. Due to the high heterogeneity ( I 2 = 100%, p < .00001) observed in our study, a random effect model was used for the analysis. The pooled odds ratio was 0.84 (95% CI: 0.50, 1.43), p (overall effect) = .53), indicating that herpes zoster vaccination reduces the risk of dementia. Conclusion Herpes zoster vaccination is associated with a reduction of the risk of dementia. More epidemiological studies are needed to confirm the association.