This Common Vaccine May Slow the Progression of Dementia or Even Prevent It

A common shingles vaccine may help slow the progression of dementia and reduce the risk of early memory decline, according to new research.

Researchers analyzed health records from more than 300,000 people in Wales between 2013 and 2022. The study found that the herpes zoster (HZ) vaccine — the medical term for the shingles vaccine — “slows or prevents disease progression across the entire disease course of dementia,” according to findings published in the medical journal Cell.

Among people already living with dementia, those who received the vaccine had a 29.5% lower risk of death. For individuals who had not yet been diagnosed, vaccination reduced the likelihood of developing cognitive impairment by 3%.

The protective effect was more pronounced in women than in men, with researchers noting that the vaccine’s impact on both new diagnoses of mild cognitive impairment and dementia-related deaths was stronger among women.

“These findings suggest the vaccine doesn’t just have preventive potential, but may also offer therapeutic benefits,” said Dr. Pascal Geldsetzer, an assistant professor of medicine at Stanford University and senior author of the study, in comments to CNN. “We’re seeing benefits even among those who already have dementia, which was unexpected and very exciting.”

The shingles vaccine is administered as a two-dose series, typically recommended at age 50, or starting at age 19 for adults with weakened immune systems, according to guidance from the U.S. Centers for Disease Control. About one in three adults will develop shingles in their lifetime, a condition known for causing a painful, itchy rash and, in many cases, long-term nerve pain.

Shingles is caused by the same virus responsible for chickenpox. Even after recovery from chickenpox, the virus can remain dormant in the body for years before reactivating as shingles, which is why vaccination is recommended even for those who have previously had chickenpox.

To strengthen their findings, researchers took into account vaccine eligibility rules in Wales. This allowed them to compare groups who were eligible for vaccination with those who were not, helping reduce differences related to lifestyle factors such as diet or physical activity.

“As a result, we’re much more confident that we’re observing a cause-and-effect relationship rather than simple correlation,” Geldsetzer explained.