The increasing prevalence of dementia and Alzheimer’s disease has prompted researchers to investigate potential preventative measures. A recent study conducted by Stanford Medicine indicates that the shingles vaccine, traditionally used to prevent the painful viral rash, may also play a role in lowering dementia risk among older adults.

Previous Findings and Study Limitations

Prior research suggested a correlation between shingles vaccination and a decreased risk of dementia. However, many of these studies were confounded by factors such as the generally healthier lifestyle of individuals who choose to get vaccinated, making it challenging to ascertain whether the observed protective effect was genuinely due to the vaccine or associated lifestyle habits.

A Unique Opportunity for Research

To gain clearer insights, the Stanford team leveraged a unique public health policy in Wales. In 2013, a targeted shingles vaccination initiative created a distinct eligibility criterion based on age, allowing those who turned 79 by September 1 to receive the vaccine, while those who turned 80 before that date were ineligible. This design created two comparable groups with similar demographics, enabling a more accurate assessment of the vaccine’s direct impact on dementia risk.

Dr. Pascal Geldsetzer, the senior author of the study, noted, “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.”

The Power of Vaccination

The findings were significant: individuals who received the shingles vaccine were found to be 20% less likely to develop dementia within a seven-year timeframe compared to those who did not get vaccinated. Importantly, the study indicated that this protective effect was more pronounced in women than in men, potentially reflecting differences in immune responses or variations in dementia pathology between sexes.

A Groundbreaking Conclusion

Dr. Geldsetzer emphasized the importance of these findings by stating, “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.”