Plate Nº 68 · recorded October 10, 2026
Health & Medicine ResearchReported finding
Shingles Vaccine Tied to 24% Lower Dementia Risk in Older Adults
Shingrix vaccination was linked to a 24% lower dementia risk over four years in a Brown study of 500,000 nursing home residents, with roughly one case prevented per 17 vaccinated.
By Marcus Bennett3 min read575 words
In brief
- Vaccinated adults had a 24% lower dementia risk over four years
- Study analyzed 509,926 nursing home residents age 66 and older
- Only 8,843 of 509,926 residents had received the Shingrix vaccine
- 18.8% of vaccinated vs 24.6% of unvaccinated developed dementia
- Published August 25, 2026 in Annals of Internal Medicine
Older adults who received the Shingrix shingles vaccine were 24% less likely to develop dementia over the following four years, a Brown University study of more than 500,000 nursing home residents found.
The analysis, published August 25 in Annals of Internal Medicine, adds to a growing body of evidence that vaccination against shingles — a painful rash caused by the reactivated chickenpox virus — may also help protect the aging brain.
What did the researchers find?
Among 509,926 adults age 66 and older in the study, only 8,843 had received at least one dose of Shingrix after entering a skilled nursing facility between 2017 and 2022. Over four years of follow-up, 18.8% of vaccinated residents developed dementia, compared with 24.6% of those who remained unvaccinated.
"This translates to about one in 17 dementia cases potentially being prevented," said lead author Kaley Hayes, an assistant professor at Brown University's School of Public Health.
Shingrix, also known as the recombinant zoster vaccine (RZV), replaced an older shingles shot after its 2017 approval and is the only shingles vaccine available in the United States.
Why study nursing home residents?
The researchers drew on Medicare claims and electronic health records from more than 5,500 skilled nursing facilities nationwide. Residents entering these facilities face a "very clear clinical point in care," Hayes said, where vaccination decisions happen routinely.
Each participant had to be eligible for shingles vaccination and free of any prior dementia diagnosis. The team used a method called target trial emulation, a statistical approach that mimics a randomized clinical trial when running a true trial is impractical.
What are the limitations?
The study cannot prove that Shingrix itself caused the lower dementia rates. Residents who got vaccinated tended to be slightly younger and healthier than those who did not — traits that could independently reduce dementia risk.
The researchers adjusted their analysis for these factors and found they did not fully explain the gap. But hidden variables the team could not measure — a problem called residual confounding — may still play a role.
Randomized clinical trials will be required to confirm whether the vaccine directly protects the brain.
Does this fit a larger pattern?
Yes. Several earlier studies of the older shingles vaccine, called Zostavax, also linked vaccination to lower dementia risk. The new analysis extends that pattern to the recombinant vaccine used today.
"It fits into this large puzzle that's just starting to come together that the vaccines are effective at preventing shingles and also appear to have neuroprotective benefits," said Hayes, who also serves as associate director of pharmacoepidemiology at Brown's Center for Gerontology and Healthcare Research.
Scientists still do not know why a shingles vaccine might shield the brain. One leading hypothesis holds that blocking viral reactivation reduces inflammation that drives neurodegeneration.
What happens next?
Researchers hope the results will trigger clinical trials testing Shingrix specifically for dementia prevention. If the link proves real, a single widely available vaccine could protect against two diseases affecting millions of older adults.
"Our cognition is so tied to our overall health and what happens to us physically," Hayes said. "It's really amazing to see that something that's supposed to prevent a physical ailment can also help keep our brain healthy, too."
Funding and conflicts
The authors reported receiving funding from GlaxoSmithKline, which makes Shingrix. They stated the company had no role in study design, analysis, or the decision to publish.
via brown.edu (Original)
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