Shingles Shot May Help Protect the Brain

The shingles vaccine, already recommended for adults 50 and older to prevent a painful rash, may also offer another benefit: a lower risk of dementia.

Researchers at Stanford University studied a vaccine rollout in Wales that created a natural experiment. Because eligibility was based on age, researchers were able to compare similar groups of older adults who did and did not receive the shingles vaccine.

They found that people who received the shot were about 20% less likely to develop dementia over the next seven years.

A follow-up study published in Cell in December 2025 suggested the vaccine might also slow the decline in some people who already have dementia.

Researchers are still trying to understand why.

One theory involves the virus that causes chickenpox and shingles. After a person has chickenpox, the virus remains dormant in the nerves for life and can reactivate years later as shingles. Scientists suspect that repeated reactivation may contribute to brain inflammation.

By keeping the virus under control, the shingles vaccine may reduce some of that inflammation.

The research has also found that the possible protective effect appears stronger in women than in men, though scientists do not yet know why.

The findings do not prove that the shingles vaccine prevents dementia, and more research is needed to understand the connection. Still, they add to growing evidence that preventing certain infections may offer benefits beyond avoiding the illness itself.

For adults already considering the shingles vaccine, protection against shingles remains the main reason to get it. Any potential brain benefit may be an added bonus.