A growing body of research suggests the shingles vaccine may do more than prevent a painful rash, it could help lower your risk of dementia.
After falling ill with chickenpox, it never truly leaves the body, making home in your nerve cells for life and reawakening decades later causing shingles. However, scientists now believe those reactivations may also quietly damage the brain over time, and that preventing reactivations could protect against cognitive decline.
A landmark 2025 study in Nature used a clever natural experiment in Wales, where a strict birthday cutoff determined who could get the shingles vaccine. People born just one week apart were essentially identical, except one group was eligible for vaccination and the other was not.
Over seven years, those eligible for the vaccine had a 20 percent lower chance of being diagnosed with dementia. That finding has been reinforced by multiple large studies of the newer, more effective shingles vaccine (Shingrix).
A Kaiser Permanente study of over 300,000 adults found vaccination was linked to a 51 percent lower dementia risk; the reduction held up even after accounting for the fact that healthier people tend to get vaccinated.
Most recently, a study published in the Annals of Internal Medicine examined more than 500,000 older adults admitted to skilled nursing facilities, a population known to be at high risk for dementia. Researchers found that those who received the shingles vaccine had a 24 percent lower risk of dementia over four years.
Why might this work?
A recent editorial in Clinical Infectious Diseases outlines three possible explanations.
First, the vaccine may reduce the cumulative burden of virus reactivation, including episodes so mild they go unnoticed, that can inflame and injure brain tissue over time.
Second, the vaccine may reshape the aging immune system in ways that dial down chronic, harmful inflammation linked to dementia.
Third, shingles can damage blood vessels in the brain, and preventing those episodes may protect against vascular injury that contributes to cognitive decline.
While these studies are observational, the consistency of the signal across different populations and countries is leading researchers to call for clinical trials to deeper investigate the biological mechanisms. In the meantime, the shingles vaccine is already recommended for adults 50 and older. If it also helps protect the brain, that’s one more reason to discuss it with your doctor.
Dr. Michael Baltes is the medical director of primary care services with Compass Health Network.
