Unexpected Benefits of the Shingles Vaccine: Potential Dementia Protection
It’s fairly common for medical treatments to cause side effects like headache or upset stomach—and occasionally a side effect provides an unexpected benefit. Emerging evidence suggests the shingles vaccine may be one such case, potentially reducing the risk of dementia.
Understanding Shingles and Vaccination
Shingles is a painful, blistering skin rash caused by reactivation of the varicella zoster virus, the same virus responsible for chickenpox. After chickenpox, the virus remains dormant in nerve tissue and can later reactivate.
A shingles vaccine is recommended for:
- Adults ages 50 and older
- People 19 and older with an impaired immune system
Vaccination and Dementia Risk
Dementia affects an estimated nine million people in the US—a number expected to double by 2060. Most cases lack highly effective treatments, so a preventive measure that is safe, inexpensive, and already available could have enormous impact.
Some studies have linked a history of shingles with higher future dementia risk, prompting research into whether preventing shingles via vaccination might lower that risk. Several observational studies suggest it does.
Key Study: Natural Experiment in Wales
Perhaps the strongest evidence comes from a natural experiment published in Nature. In 2013, Wales made the shingles vaccine available based on date of birth: anyone born after September 2, 1933, was eligible, while anyone born before was not. Researchers compared health records of nearly 300,000 people—those born two weeks before the cutoff versus two weeks after—over a seven-year period.
Findings
Compared to those who didn’t receive the vaccine, vaccinated individuals had a significantly lower risk of developing dementia during follow-up.
Need for Further Research
A study of this type cannot prove causation, but alongside other research, it strongly suggests shingles vaccination may prevent dementia. Additional studies are needed to confirm the benefit, determine whether it applies to specific dementia types (e.g., Alzheimer’s disease), and assess how protection changes over time.
Biologic Plausibility
Scientists refer to the existence of a reasonable explanation for an unexpected finding as biologic plausibility. In this case, several lines of reasoning support how preventing shingles could reduce dementia risk, increasing confidence that the result will hold up in future research.
Gender Differences
Researchers observed that women appeared to gain more dementia protection from the vaccine than men. This difference remains unexplained but could relate to variations in immune response or dementia development between sexes.
Other Ways to Lower Dementia Risk
All of us can take steps to reduce dementia risk through healthy behaviors:
- Regular physical activity
- Choosing a healthy diet
Conclusion
Evidence is mounting that shingles vaccination should join the list of dementia-risk–lowering strategies. It can prevent painful shingles episodes—and may do much more. If you’re eligible, get your shingles vaccine.