Can the Shingles Vaccine Lower Dementia Risk?What the Wales Study Found, and Its Critics
SkinArticleA 2025 study in Wales used a birth-date cutoff to compare similar older adults and found the older live shingles vaccine was linked to about 20% fewer new dementia diagnoses, with a stronger effect in women. A 2026 analysis argued similar studies imply impossibly large effects. Either way, the reason to get vaccinated is to prevent shingles and its lasting nerve pain.
Some herpes viruses may play a role in dementia, so researchers have wondered whether preventing shingles could protect the brain.1 A widely reported 2025 study suggested it might.
The Wales study
In Wales, eligibility for the older live shingles vaccine depended on exact date of birth. People born just one week apart had very different vaccination rates: 0.01% vs. 47%.1 Because those groups were otherwise similar, researchers could compare them almost like a randomized trial.1
- Over 7 years, getting the vaccine was linked to 3.5 percentage points fewer new dementia diagnoses, about a 20% relative reduction.1
- The effect was stronger in women than men.1
The pushback
A 2026 analysis looked at this and similar natural experiments from Australia and Canada.2 When it calculated how big the vaccine effect would have to be to explain the results, two estimates came out over 100%, which is impossible.2 It also found no drop in national dementia rates after vaccination programs began.2 The authors concluded these studies aren’t strong evidence of a meaningful effect and need independent confirmation.2
An important difference
The studies looked at the live vaccine. The vaccine offered in the U.S. today is a recombinant vaccine given in two doses.13 Whether it affects dementia risk isn’t settled by these studies.
The solid reason to get vaccinated
- About 1 in 3 people in the U.S. will get shingles.3
- The vaccine is over 90% effective at preventing shingles and long-lasting nerve pain in adults 50 and older with healthy immune systems.3
- That nerve pain can last months or years.3
- It’s recommended for adults 50 and older, with no upper age limit.3
Our guides to shingles vaccine costs and side effects and when shingles needs prompt care cover the details.
Try: “I’m 62 and haven’t had the shingles vaccine. Is now a good time, and what side effects should I plan for?”
Skin, Head to Toe includes a short-shelf planner and a 12-week SkinLog. Use them to note your vaccine dates and any rash or skin changes. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please talk with your clinician or pharmacist about which vaccines are right for you. A painful rash in a band on one side of the body, especially near the eye, needs prompt care. New memory problems should be evaluated. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses published research and public health guidance. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- Nature (full text via PubMed Central), 2025A natural experiment on the effect of herpes zoster vaccination on dementia (opens in a new tab)abcdef
- Brain, Behavior, and Immunity (abstract via PubMed), 2026Natural experiments of herpes zoster vaccination: Quantifying the implied vaccine effectiveness against dementia (opens in a new tab)abcd
- Centers for Disease Control and PreventionShingles Vaccination (opens in a new tab)abcde
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