Shingles or herpes zoster (HZ) is a neurotropic virus that causes a painful and hard to treat illness. Evidence is accumulating that HZ vaccinations might lower the risk of dementia. This effect is surprising but well-documented; here are 3 recent meta-analyses:
An international team of scientists aimed to evaluate the association of HZ infection, protective effects of antiviral treatment or vaccination on dementia. Systematic searches of PubMed, MEDLINE, EMBASE, Scopus, Web of Science, CINAHL, and Cochrane CENTRAL was performed from January 1, 1996, to October 31, 2024. Observational studies evaluating HZ infection, antivirals, or vaccination and dementia risk were selected. Risk of bias was examined with the Newcastle-Ottawa scale. A random-effects meta-analysis was performed, with the rate ratio (RR) and corresponding 95% confidence intervals (CIs) being pooled for dementia. Presence of heterogeneity was assessed with I2, and differences by study-level characteristics were estimated using subgroup meta-analysis and meta-regression.
Eighteen studies (N = 9.4 million) were included. Infection was associated with elevated risk of dementia (RR 1.14; 95% CI: 1.04, 1.25, I2 = 98%); this remained significant in the sensitivity analysis when the two case-control studies were removed (RR 1.17; 95% CI: 1.06, 1.30, I2 = 98%). Subgroup analysis based on sex, age, study population, bias scores, type of dementia or HZO did not show statistically significant differences in risk. Treatment with antivirals showed a small effect (RR 0.84; 95% CI: 0.71, 0.99, I2 = 73%), but prophylaxis with HZ vaccination was associated with a significantly lower risk (RR 0.68; 95% CI: 0.56, 0.83, I2 = 99%).
The authors concluded that there is a slightly raised dementia risk after HZ infection and reduced risks after antiviral treatment and prevention with vaccination. However, results should be interpreted with caution due to significant heterogeneity in pooled analyses.
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. An Indian/American team 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. The researchers 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 (I2 = 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.
The authors concluded that herpes zoster vaccination is associated with a reduction of the risk of dementia. More epidemiological studies are needed to confirm the association.
Herpes zoster (HZ) infection may increase the risk of dementia, that causes a heavy socioeconomic burden. However, the epidemiological evidence between HZ vaccination and the risk of dementia remains inconclusive. This meta-analysis was conducted to investigate the effect of HZ vaccination on the onset of dementia. The researchers searched PubMed, EMBASE, Web of Science, Science Direct, and Scopus for cohort studies assessing the association between HZ vaccination and dementia risk up to 20th January 2025. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled adopting a random-effect model. Four eligible studies were included in the systematic review and five retrospective cohort studies in the meta-analysis. Among 14,493,383 dementia-free participants at baseline, 427,309 dementia cases occurred during 36-95 months of follow-up. All studies were of high quality. Pooled analysis of adjusted HRs indicated that HZ vaccination could reduce dementia risk by 29% (HR = 0.71, 95% CI: 0.66-0.76, I2 = 97.15%). Subgroup analyses revealed heterogeneity linked to definitions of dementia, exposure measurements, vaccination doses, deprivation index, and region. The results were stable in the sensitivity analyses, and no publication bias was found.
The authors concluded that HZ vaccination was notably related to a reduced risk of dementia. More mechanistic studies and epidemiological studies are warranted.
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The effect seems powerful and faily consistent across different studies. But how can this be? Australian neuroscientists have suggested that subclinical zooster virus reactivation might act as a renewable peripheral immune stressor, amplifying microglial priming in aging brains. Shingles vaccination may suppress this viral reservoir, reducing cumulative inflammatory tone.
Whatever the mechanism, the news that zoster vaccination might strongly reduce the dementia risk is hugely encouraging. It could also, I hope, have the effect that the dangerous anti-vaccination attitude currently fuelled by the incompetent US govenment will be getting a little less popular.
PS
Needless to say that these vaccinations also reliably prevent shingles!
So please, do consider getting vaccinated.
6 Responses to Shingles vaccination is associated with a powerful reduction of the risk of dementia
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I am taking a page from anti-vax playbook and making this proclamation:
SHINGLES JAB GIVES YOU SUPER POWERS! That makes me wonder what other vaccines give you super powers. They don’t want you get super powers. They are hiding the truth from us. Go get jabbed to become superman!!!
Hi Prof. Ernst,
thanks for the info, but
do you know if the potential protective effect of the vaccination also exist if the person already was infected with the shingles virus?
In other words, does it make sense to get the vaccination AFTER you already had shingles (Gürtelrose)?
yes
Although I am not yet 60 yo, I just had the first dose of Shingrix.
After experiencing shingles several years back, I know how painful such an outbreak is. With the added benefit of a somewhat reduced risk for dementia, the Shingrix vaccination is a no-brainer in my opinion.
Thanks for covering the topic!
“You can get shingles more than once, so it’s important to get vaccinated even if you’ve had shingles before.”
— Shingles. NHS.
Interesting, thanks!