• Posted December 3, 2025

Shingles Vaccine May Help Slow Dementia, New Study Finds

A routine shingles shot may do more than prevent a painful rash. It could also support long-term brain health, new research shows.

In a study published Dec. 2 in the journal Cell, Stanford University researchers found that adults who received the shingles vaccine were less likely to develop early memory and thinking problems.

And among those who already had dementia, getting the vaccine was linked to a lower risk of dying from the disease.

"We see an effect on your probability of dying from dementia among those who already have dementia," senior author Dr. Pascal Geldsetzer, an assistant professor of medicine at Stanford in California, told CNN.

"That means that the vaccine doesn’t just have a preventive potential, but actually a therapeutic potential as a treatment, because we see some benefits already among those who have dementia," he added.

The findings come from health data of more than 282,500 older adults in Wales, where a shingles vaccine program began in 2013.

Because only people who were 79 years old on a specific date were eligible for the vaccine while adults who had just turned 80 were not, researchers were able to compare two very similar groups with very different vaccination rates.

Earlier analysis showed a 3.5-percentage point decrease in dementia diagnoses over seven years among these vaccinated folks.

The new analysis expanded on that:

• Adults who had no prior memory problems and got the shingles vaccine had a 3.1-percentage point lower risk of developing mild cognitive impairment over nine years versus those who didn't get it.

• Among folks already living with dementia, vaccination was linked to a 29.5-percentage-point lower chance of dying from dementia over nine years.

• As was the same in the earlier study, the protective effects appeared stronger in women.

Scientists are still trying to figure out the “why.”

But Geldsetzer said two ideas may explain the findings:

1. Lower inflammation in the nervous system: After a childhood chickenpox infection, the virus stays dormant in the nervous system. Even while "asleep," it can create ongoing immune activity. Since inflammation plays a major role in dementia, preventing these reactivations might have benefits for the dementia process.

2. A stronger immune system overall: Vaccines don’t only create antibodies, they also play a broader role in making the immune system stronger. Because many infections are tied to dementia risk, an immune system that's ready to fight off infection may help protect the brain.

“These kinds of broader immune system activations may well have benefits for dementia disease development as well, and we know the immune system plays a key role in dementia. So that’s the other mechanism," Geldsetzer explained.

Angelina Sutin, a behavioral sciences professor at Florida State University in Tallahassee, who was not involved in the research, explained that the findings are encouraging.

"When people find out that I study dementia, they often ask what I recommend to keep the brain healthy with age. I always respond with three things: exercise, be social, and do things you enjoy that make you feel purposeful," she told CNN in an email.

"Now, I will add talk to your doctor about getting the shingles vaccine. There is no guarantee that doing these things means you will not get dementia, but all are relatively easy and accessible and help maintain healthy cognition for longer," Sutin added.

Other experts stressed that more studies are needed, however.

"I would view these results as promising, providing unique evidence that shingles vaccination may have meaningful cognitive benefits, but not yet as definitive proof that we should vaccinate solely for dementia risk reduction," Dr. Joel Salinas, a neurologist at NYU Langone in New York City, said to CNN.

"This study is a very important advance in understanding because it provides the closest to causal evidence for the shingles vaccine that is possible. Unfortunately, it does not directly answer the why," Sutin said. "This research sets a strong foundation for future research to find out why it is so protective."

More information

The Cleveland Clinic has more on the shingles vaccine.

SOURCE: CNN, Dec. 2, 2025