Introduction to Shingles Vaccine and Dementia
Getting vaccinated against shingles — a painful and debilitating condition that can flare up years after infection from varicella zoster — not only lowers the risk of infection, but may also offer some protection against dementia, a provocative new study suggests.
Research Findings
The new research, published Wednesday in Nature, analyzed data from more than 280,000 older adults in Wales and found that people who received the original shingles live virus vaccine were 20% less likely to develop dementia of any type than those who were not vaccinated. Previous research has found an association between the Shingrix shingles vaccine, which replaced the live virus version in 2020, and a lower risk of dementia, especially in women.
Study Design and Methodology
The new study was possible because of an unusual public health policy in Wales that provided a “natural experiment” to explore the potential impact of the vaccine on dementia risk. With the rollout of the vaccine in 2013 in Wales, shots were offered to people born on or after Sept. 2, 1933, but not those who were born before that date. That allowed the German and Stanford University researchers to compare two groups of people with similar health characteristics who differed only by one week in age, making them essentially the same except that the vaccine was available to the younger population but not the older, said Dr. Pascal Geldsetzer, an assistant professor of medicine at Stanford University and senior author of the study.
Expert Insights
What’s exciting about the study is that it’s essentially like a randomized controlled trial, considered the gold standard in research, he said. The way the original vaccine was rolled out in Wales provided a unique opportunity, said Allison Aiello, a professor of epidemiology at the Columbia University Aging Center in New York City. “It’s like having a control group compared to a treated group,” said Aiello, who was not associated with the new research. “What’s interesting is the finding of 20% protection. That is a pretty strong effect, which does fit with other research suggesting that herpes viruses might have an influence on dementia.”
Understanding the Link Between Shingles and Dementia
Scientists don’t know exactly how the chickenpox virus raises the risk of dementia. It’s been shown that reactivation of the virus can lead to the accumulation of aberrant proteins associated with Alzheimer’s, for example, Geldsetzer said. It’s also possible that the virus might spark a reactivation of herpes simplex, which earlier research has linked to dementia. Herpes viruses never completely go away, but instead lurk in the body until the immune system weakens. Aging leads to a natural weakening of the immune system that can allow the virus to resurface as shingles, a nasty side effect of chickenpox.
Shingles Vaccine and Age
The age effect is why the shingles vaccine has been offered only to people age 50 and older in the U.S. It’s given as two doses, two to six months apart. Herpes viruses, including oral and genital herpes simplex, appear to have the ability to get into the central nervous system, experts said. In fact, a 2024 study found that among 70-year-olds without dementia at the outset, older adults with a herpes simplex diagnosis were more than twice as likely as uninfected people to develop dementia over a 15-year follow-up.
Additional Research and Findings
Bolstering the case for the shingles vaccine protecting against dementia were the findings from a study published in Nature Medicine in 2024 that analyzed medical records from more than 100,000 patients. That analysis suggested the newer shingles vaccine was associated with even better protection against dementia. In that study, researchers also investigated whether two other vaccines — for influenza and tetanus, diphtheria and pertussis — had any impact on the risk for dementia. They did not.
Conclusion
The most important take-home message from the Stanford study is that getting vaccinated might lower the risk for dementia, said Dr. Aarati Didwania, a professor of medicine and medical education at Northwestern University’s Feinberg School of Medicine in Chicago. Exactly how the vaccines might protect against dementia isn’t clear, Didwania said. “But it’s an intriguing question,” she added. “Is it by decreasing inflammation or preventing the virus from reactivating?” There’s certainly a good reason for getting vaccinated, Didwania said. “Shingles is a terrible, painful and debilitating condition that can lead to horrendous long-term pain,” she said.
FAQs
- Q: What is the main finding of the new study on shingles vaccine and dementia?
A: The study found that people who received the original shingles live virus vaccine were 20% less likely to develop dementia of any type than those who were not vaccinated. - Q: How was the study conducted?
A: The study analyzed data from more than 280,000 older adults in Wales, comparing those who received the vaccine to those who did not, based on a unique public health policy rollout in Wales. - Q: What is the potential link between shingles and dementia?
A: Scientists believe that reactivation of the chickenpox virus may lead to the accumulation of aberrant proteins associated with Alzheimer’s, or spark a reactivation of herpes simplex, which has been linked to dementia. - Q: Who should get the shingles vaccine?
A: The shingles vaccine is offered to people age 50 and older in the U.S., given as two doses, two to six months apart. - Q: Are there any limitations to the study?
A: While the study indicates the benefit of the vaccine in a real-world setting, it’s not the same as a randomized controlled trial, and there are limitations to its design.
