As dementia and Alzheimer’s cases continue to rise, researchers are exploring new ways to curb their impact. But a surprising breakthrough suggests that protection might already be within reach. A recent study suggests that shingles vaccine, which protects against the painful viral rash, may also reduce the risk of dementia in older adults.
Earlier studies have shown that there is reduced dementia risk among those vaccinated with shingles. However, many were biased, as vaccinated individuals tend to be more health-conscious, making it difficult to determine whether the vaccine itself offered protection or if lifestyle factors like diet and exercise played a role.
To address this, researchers at Stanford Medicine took advantage of an unusual public health policy in Wales. In 2013, a shingles vaccination program set strict age-based eligibility rules: those who were 79 on September 1 could receive the vaccine that year, while those who turned 80 before the cutoff were never eligible.
The two groups had similar education levels, vaccination habits, and rates of conditions like diabetes and heart disease. This created a unique opportunity to compare two nearly identical groups, differing only in vaccine access, allowing researchers to isolate the vaccine’s true impact from lifestyle factors.
“What makes the study so powerful is that it’s essentially like a randomized trial with a control group — those a little bit too old to be eligible for the vaccine — and an intervention group — those just young enough to be eligible,” said Dr. Pascal Geldsetzer, senior author of the study in a news release.
The study showed that those who received the shingles vaccine were 20% less likely to develop dementia over the next seven years than those who did not receive the vaccine. The researchers also noted that the protection against dementia was notably stronger in women than in men. This is possibly due to sex differences in immune response or the difference in the way dementia develops.
“For the first time we are able to say much more confidently that the shingles vaccine causes a reduction in dementia risk. If this truly is a causal effect, we have a finding that’s of tremendous importance,” Dr. Geldsetzer added.