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When a virus hides in your body for decades, it can sometimes cause trouble later in life. That’s what happens to some people who get shingles — a virus that causes a painful rash and affects millions of older adults every year. New research suggests this virus can do more than cause pain, though. It could also play a role in some of the causes of Alzheimer’s disease and other forms of dementia. The good news is that by protecting yourself with the shingles vaccine, you may be able to lower your risk for dementia, too.
In this article, we’ll discuss what scientists are learning about the link between shingles, dementia, and Alzheimer’s disease. We’ll also share what the latest research shows about the potential neuroprotective (brain-protecting) effects of the shingles vaccine.
Shingles happens when the varicella zoster virus — the chickenpox virus — wakes up again years later. Even after you recover from chickenpox, the virus stays in your body. It lives silently in the nervous system, specifically in nerve cells in the face and spine.
As people get older, the immune system weakens. This can make it more likely for the virus to reactivate, leading to shingles, also called herpes zoster. Shingles causes burning pain, itching, and a rash that may take weeks to go away. Some people develop postherpetic neuralgia (long-term nerve pain), which can last for months or even years. People over 50 and those with a weakened immune system are most at risk.
“I had shingles some years back, right before I was old enough for the first shingles vaccine,” one myALZteam member shared. “It was extremely painful, but fortunately, I had no lingering effects. I know that the older we get, the harder shingles is on our bodies.”
Doctors are learning that shingles may affect more than just the skin. It can also reach the brain and other parts of the nervous system. When the virus reactivates, it can travel along nerve fibers and cause inflammation in the brain and spinal cord. This inflammation may damage nerve cells and disrupt how the brain communicates, leading to problems like hearing loss, vision or balance changes, or even temporary paralysis.
Over the past few years, researchers have found links between shingles and a higher risk of dementia. Studies using large health records have shown that people who develop shingles are 20 percent more likely to experience cognitive decline (thinking problems) — one of the earliest signs of Alzheimer’s and other forms of dementia. Scientists believe this may happen because inflammation caused by the virus speeds up neurological (brain-related) changes related to dementia.
In a 2024 study published in the journal Alzheimer’s Research & Therapy, researchers noted that the risk was strongest in men who carry the APOE4 gene. This gene is known to increase the likelihood of Alzheimer’s disease.
One myALZteam member described “a bad case of shingles” on the right side of their wife’s head and face, including the ear. “A very few years later, we started seeing her first signs of declining memory, and we got an official diagnosis of Alzheimer’s a couple of years after that,” the member said.
Recent studies suggest that protecting yourself from shingles may also protect your brain health. The shingles vaccine has shown promising signs of lowering the risk of dementia in older adults. Despite these results being very important and promising, they are not conclusive, and future studies may help clarify the link further.
In the 2024 study, the researchers analyzed a large dataset of over 149,000 participants. The study confirmed earlier reports showing that people with a history of shingles were more likely to experience cognitive decline. Importantly, among women in the study, those who weren’t vaccinated against herpes zoster had a higher long-term risk of cognitive decline compared with those who had been vaccinated.
These findings mirror earlier reports, where adults who received a shingles vaccine had about a 20 percent lower risk of dementia compared with unvaccinated adults. Other studies from the past few years show similar patterns.
Scientists are still studying how the shingles vaccine might protect against dementia. One idea is that herpes zoster vaccination could prevent viral infection, which can directly harm the brain. In turn, this may reduce inflammation in the brain. Chronic inflammation has long been linked to neurological damage and may play a role in the development of Alzheimer’s disease.
Another possible factor is that vaccination strengthens the immune response. This could help the body respond more effectively to infections that could harm the brain.
Researchers have also noticed that the vaccine’s benefits against dementia may fade after several years. This might mean that the shot delays, rather than completely prevents, the start of dementia symptoms. However, this pattern hasn’t been seen in all studies, so more research is needed to confirm it.
There are two main types of shingles vaccines that have been used in the U.S.: the older Zostavax and the newer Shingrix. Both help prevent shingles, but they work in different ways.
Zostavax is a live-attenuated vaccine. This means it uses a weakened form of the virus to train the immune system. It was first approved by the U.S. Food and Drug Administration (FDA) in 2006, and it can reduce the risk of shingles by about 50 percent. Several studies show that adults who received Zostavax had a lower risk of developing dementia compared to those who weren’t vaccinated. However, the protection faded over time. Zostavax is no longer available in the U.S.
Shingrix is now the only shingles vaccine available in the U.S. It’s a recombinant zoster vaccine, so it doesn’t use live virus. Instead, it contains a piece of the virus and an adjuvant — an immune-boosting ingredient — that helps create a stronger response.
A new study published in the journal Nature Medicine found that people who got Shingrix showed an even greater protective effect against dementia than those who received Zostavax. This protective effect appeared slightly stronger in women, who showed a lower risk of cognitive decline after vaccination compared to men.
While the research is encouraging so far, many questions remain. Scientists still don’t know exactly how the shingles vaccine lowers Alzheimer’s risk or how long the protection lasts. It’s also unclear whether the vaccine works the same for everyone or if certain risk factors — like age, sex, or genetics — change its effects.
So far, most studies have been observational. This means they show a link but can’t prove cause and effect. Large clinical trials will be needed to confirm whether the vaccine truly prevents dementia or simply delays it. Researchers also hope to learn whether other vaccines might offer similar protection for brain health.
Unfortunately, Alzheimer’s disease can’t yet be cured or reversed. However, some medications may help with symptoms. That’s why prevention and early intervention are so important.
Getting the shingles vaccine is a simple step you can take to protect your body and your brain for years to come. For families already caring for someone with dementia, it’s important to talk to a healthcare team about medications to avoid. This is because some drugs can worsen memory or confusion. With small steps, you can improve comfort, safety, and long-term health outcomes for loved ones.
On myALZteam, people share their experiences with Alzheimer’s disease, get advice, and find support from others who understand.
What other questions do you have about vaccines and Alzheimer’s risk? Let others know in the comments below.
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