Can Vaccines Really Help Prevent Dementia? - Gizmodo

What the report says

Gizmodo reported that scientists are increasingly examining whether vaccines, especially shingles shots, could have a role in lowering dementia risk. The article, published July 25, 2026, centers on evidence suggesting shingles infection may contribute to later cognitive decline, while vaccination against varicella zoster virus could be linked to fewer dementia diagnoses. One recent study cited by Gizmodo found nursing home residents who received a shingles vaccine were less likely to be diagnosed with dementia during a four-year period than unvaccinated residents.

The article emphasizes that the case is not settled. Many of the encouraging findings are observational, so they can show associations but not prove that vaccines directly prevent dementia. Some studies have used methods meant to strengthen causal interpretation, but researchers including UK epidemiologist George Davey Smith have questioned whether the current evidence is strong enough to support vaccination specifically as a dementia-prevention strategy.

Experts quoted by Gizmodo described several possible biological reasons the idea remains plausible. Alison Aiello of Columbia University noted that herpesviruses have long been studied in relation to dementia, while the shingles virus is notable because it has vaccines. William Eimer of Mass General Research Institute said Alzheimer’s research is broadening beyond amyloid and tau to consider possible roles for infections and immune responses.

The public-health stakes are significant: Gizmodo notes about 7 million Americans are living with Alzheimer’s disease, with that number potentially much higher by mid-century. The report also says GSK has begun a large Finnish study to test whether its shingles vaccine can reduce dementia risk, which could help clarify whether the observed link is causal.