It’s the shingles shot again.

this week delivered one of the brightest spots in an otherwise dark field. According to a study that followed more than 280,000 people in Wales, older adults who received a vaccine against shingles were 20 percent less likely to develop dementia in the seven years that followed vaccination than those who did not receive the vaccine.

This could be a big deal. There are very few, if any, treatments that can prevent or slow down dementia, beyond good lifestyle habits like getting enough sleep and exercise. The possibility that a known, inexpensive vaccine could offer real protection is enormously meaningful. We have good reason to be confident in the findings: While this study is perhaps the most prominent to show the protective effects of the shingles vaccine, other studies of the vaccine have come to similar conclusions.