Reduce Your Risk For Dementia

A growing body of international research suggests that vaccinations for shingles and the flu may significantly reduce the risk of developing dementia and Alzheimer’s disease in older adults.

Researchers emphasized that their studies do not prove that vaccination will prevent dementia or Alzheimer’s disease, only that vaccination is associated with a reduced risk of these diseases. However, scientists believe their studies are helping them get closer to identifying which factors play a key role in developing dementia and Alzheimer’s disease and how to protect against them.

Dementia is not just one disease. It is an umbrella term for a range of symptoms—including memory loss, difficulties with thinking or language, and mood changes—that are severe enough to disrupt daily activities. Alzheimer’s disease is the most common cause of dementia.

One of the latest studies, published in June in the journal Neurology, supports existing data about the connection between vaccinations and Alzheimer’s. A research team at the McGovern Medical School at UTHealth in Houston analyzed data of about 165,000 older adults who received either a high-dose flu vaccine or a standard-dose flu vaccine. The high-dose flu vaccine has four times the amount of antigen—the component that triggers an immune response—compared to the standard-dose flu vaccine, according to the Centers for Disease Control and Prevention (CDC).

The investigators discovered that over the two-year study period, people aged 65 and over who received the high-dose vaccine had a nearly 55 percent lower risk of developing Alzheimer’s disease.

The same research team published two previous studies with similar findings. The first study in 2022 associated the standard-dose vaccine with a 40 percent reduced risk of developing Alzheimer’s disease over a four-year period. The second study, published in 2023, indicated that receiving vaccines for tetanus and diphtheria, with or without boosters for pertussis, shingles, or pneumococcus, lowered the chances of developing Alzheimer’s.

Medical experts have several theories regarding the connection between the flu vaccine and Alzheimer’s.

“This is likely related to inflammation that occurs after an influenza case,” Dr. Amesh A. Adalja, an infectious disease specialist and adjunct assistant professor at the Johns Hopkins Bloomberg School of Public Health, explained to Prevention. “Inflammation has a role in the development of Alzheimer’s disease, and by blunting the inflammatory effect after viral infections, the influenza vaccine—and others—decreases the risk of Alzheimer’s disease.”

According to Dr. C. Buddy Creech, director of the Vanderbilt Vaccine Research Program, it’s possible that reducing the risk of multiple kinds of infections can reduce the inflammation and cellular damage that could contribute to Alzheimer’s. Additionally, Dr. Creech suggests that people who keep up with their vaccines might be healthier overall, which could potentially lower their risk of Alzheimer’s.

Shingles Vaccine Shows Similar Links

Research has also been conducted on the vaccine for shingles, a burning, itchy, and painful rash. Shingles is caused by the reactivation of the varicella-zoster virus, the same virus that causes chickenpox. According to the CDC, more than 99 percent of Americans born in 1980 or earlier have had chickenpox. The first chickenpox vaccine was approved in 1995.

After chickenpox is over, the virus remains dormant in nerve cells for decades. However, it can reactivate as shingles, a condition the CDC says affects about 1 million people in the United States every year.

According to Dr. Jennifer Pauldurai, the medical director of the Inova Brain Health and Memory Disorders Program in Northern Virginia, shingles can cause a “war zone” of inflammation in the brain. The shingles vaccine isn’t a “magic pill,” she said, but it can help protect against dementia.

“When the brain is stressed or challenged with any kind of illness, underlying risks of dementia become more apparent,” Dr. Pauldurai told NBC News. “We are more likely to get dementia when our brain is not as healthy as it could be, had we not gotten sick from shingles.”

What’s more, the reactivated shingles virus may trigger the accumulation of amyloid and tau in the brain, the “bad proteins” related to Alzheimer’s disease, according to Dr. Timothy Chang, an assistant professor of neurology at the Mary S. Easton Center for Alzheimer’s Research and Care at the University of California, Los Angeles.

Previous studies have shown a connection between shingles infection and a higher risk of dementia. For instance, a 2025 study published in the Journal of Prevention of Alzheimer’s Disease noted that older adults in Italy who went to the hospital because of severe shingles had a 13 percent higher risk of dementia compared to the general population.

However, a new study, published in June in the Annals of Internal Medicine, suggests that the shingles vaccination could potentially prevent 1 in 17 cases of dementia. The research team examined the health records of 509,000 adults aged 66 and older who were admitted to skilled-nursing facilities from 2017 through 2022. Individuals who received at least one dose of the shingles vaccine within a year of admission experienced a 5.8 percent reduction in dementia risk over the following four years.

“That’s huge,” Kaley Hayes, the lead study author and associate director of pharmacoepidemiology at the Brown University School of Public Health’s Center for Gerontology and Healthcare Research, told NBC News. Hayes also was surprised by the strong level of protection the vaccine provided.

Other research produced similar findings. For example, a 2025 study published in the journal Nature looked at more than 282,000 older adults in Wales and found that getting a shingles vaccination was linked with a 3.5 percent reduced chance of developing dementia over seven years.

In addition, research published in February 2026 in the journal Lancet Neurology linked vaccine eligibility to a 2 percent reduction in dementia risk over 5.5 years based on a study of more than 232,000 older adults in Canada.

Dr. Chang proposed that the shingles vaccine could potentially prevent dementia by boosting overall immune function.
“Having the vaccine remind our bodies to help improve our immunity in general —not just specifically to the vaccine—can be beneficial also to reduce neuroinflammatory processes that are going on,” Chang told NBC News.

Other studies have found that the shingles vaccine is linked to a reduced risk of dementia compared to the influenza and Tdap (tetanus-diphtheria-pertussis) vaccines.

“It’s a good excuse to get the vaccine, if you were on the edge of considering it,” Dr. Chang said.

Although staying current on vaccinations is considered “reasonable” for a brain-healthy lifestyle, it’s only one aspect of the bigger picture, according to Davide Cappon, director of neuropsychology at Tufts Medical Center.

“The strongest evidence still supports managing vascular risk factors, exercising regularly, eating a healthy diet (such as a Mediterranean-style diet), staying socially and cognitively engaged, treating hearing loss and sleep apnea, and addressing depression and anxiety,” he told Prevention. “Those interventions likely have a larger impact on long-term brain health than any single intervention.”

Story Links:

https://www.nbcnews.com/health/health-news/shingles-brain-inflammation-research-vaccine-dementia-risk-rcna351961
https://www.prevention.com/health/a71616351/vaccines-reduce-risk-alzheimers-disease-study/