Herpes Zoster Vaccination and Risk of Dementia: A Systematic Review and Meta-analysis
Sangharsha Thapa1, Sangam Shah2, Krishna Dahal2, Omid Mirmosayyeb3, Haythum Tayeb1
1Department of Neurology, Westchester Medical Center, 2Tribhuvan University, Institute of Medicine, Maharajgunj, 3Department of Neurology, University at Buffalo
Objective:
To systematically review the evidence and quantify the association between herpes zoster vaccination and risk of dementia through meta-analysis.
Background:
Prior studies have suggested that herpes zoster vaccination may reduce the risk of dementia. This systematic review and meta-analysis aimed to summarize the evidence on the association between herpes zoster vaccination and dementia risk.
Design/Methods:

Databases from their inception to December 2022 were thoroughly searched, including PubMed, EMBASE, Cochrane Library, clinicaltrials.gov, and Web of Science for case–control, cross-sectional, or cohort studies investigating the association of Herpes zoster vaccination and dementia. We took the adjusted odds ratio (OR) and 95% confidence interval (CI) from each trial to analyze the relationship between the herpes zooster vaccine and the risk of dementia. Statistical analysis was performed on the retrieved adjusted OR and 95% CI using Stata v. 16.0 (Stata Corp, College Station, TX, USA). The Newcastle-Ottawa Scale (NOS) for nonrandomized studies was employed to rate the research' quality.

Results:

We included five  high-quality studies (1 cross-sectional, 1 case-control, 3 cohort) with 103,615 vaccinated patients.  The studies were all of high quality, ranging from 7 to 9. The average result was 8.4. A random effects model meta-analysis was used due to high heterogeneity (I2=98%, p<0.00001). Our data demonstrated that patients who had  Herpes zoster vaccination were at a significantly lower risk of developing dementia. Although a significant heterogeneity (I2 = 98%, p < 0.00001) was observed in the meta-analysis, a pooled OR was estimated at was 0.76 (95% CI: 0.60,0.96), p (overall effect) = 0.02], which indicated that Herpes zoster vaccination reduces the risk of dementia. 

Conclusions:

Our Meta-analysis has demonstrated that Herpes zoster vaccination is significantly associated with reduction of risk of dementia.  However, more epidemiological studies and experiments are needed to understand the association of Herpes zoster vaccination and dementia.

10.1212/WNL.0000000000206308