Shingles Vaccine May Cut Dementia Risk by 20%

A new study shows that the Shingles vaccine may offer more than just protection from painful rashes—it could also reduce the risk of dementia. Researchers at Stanford University have found a potential link between the vaccine and a 20% decrease in dementia diagnoses, based on a detailed analysis of UK health data.

Shingles Vaccine Shows Promise in Dementia Prevention

Published in Nature, the study examined individuals in Wales, UK, where eligibility for the Shingles vaccine was determined solely by birthdate. Those born just after September 2, 1933, were eligible, while those born just before were not. This rare policy feature created a natural experiment that allowed researchers to compare similar individuals with and without vaccine access.

Over a seven-year follow-up, researchers observed a 3.5 percentage point reduction in dementia diagnoses among eligible individuals, translating to a 20% relative risk reduction.

Stronger Impact Observed in Women

The effect of the Shingles vaccine was notably stronger in women, where statistical significance was reached. In men, results were less definitive due to wider confidence intervals. Interestingly, the reduction in dementia risk became evident more than a year after vaccination, suggesting longer-term immune-related changes might be at play.

Possible Immune Benefits of Shingles Vaccination

While the Shingles vaccine is primarily used to prevent the varicella-zoster virus from reactivating, it may also reduce neuroinflammation—one of the factors linked to dementia. Scientists suggest that live-attenuated vaccines like the one used in this study might boost immune responses in a way that offers indirect brain protection.

Study Based on Zostavax, Not Shingrix

The findings are specific to the live-attenuated Shingles vaccine, Zostavax. The recombinant vaccine Shingrix, now more commonly used, was not included in this study. Future research is needed to determine if it provides similar cognitive benefits.

Shingles Vaccine Could Be a Cost-Effective Preventive Tool

With dementia continuing to rise globally and no definitive cure, this study points to this vaccine as a potential low-risk, cost-effective method for prevention. Already widely available for preventing Shingles, this vaccine may also hold unexpected promise in supporting cognitive health.

For more information: Eyting, M., Xie, M., Michalik, F. et al. (2025). A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. DOI:10.1038/s41586-025-08800-x https://www.nature.com/articles/s41586-025-08800-x