A vaccine to fight dementia? It turns out there may already be one – shots that prevent painful shingles also appear to protect aging brains.

Several previous studies have suggested that shingles vaccinations might reduce dementia risk, but most could not exclude the possibility that people who get vaccinated might have other dementia-protective characteristics, like healthier lifestyles, better diets or more years of education.

Researchers at Stanford University found evidence that suggests the shingles vaccine lowers the risk of developing dementia. Evidence from the study suggested the vaccine cut the risk of developing dementia over the next seven years by 20%. The research observed people who received a first-generation vaccine called Zostavax.