Shingles Vaccine Shows Potential in Dementia Prevention
The shingles vaccine might be an unexpected success story. While it primarily aims to prevent the varicella-zoster virus—responsible for both chickenpox and shingles—recent research suggests it may also play a role in reducing the risk of dementia, especially in women.
Data collected over the past year from various countries, including Wales, Australia, Canada, and the US, indicates that the vaccine could not only delay the onset of dementia but also slow its progression and decrease mortality rates among those already diagnosed. Interestingly, the researcher leading these studies, who is 39 years old, has personally received the vaccine, reflecting his strong belief in the promising data.
Pascal Geldsetzer, an assistant professor of medicine at Stanford, is now working to establish a clinical trial to clarify whether the relationship between vaccination and dementia risk is causal rather than merely correlational. He described the situation as “extremely exciting,” emphasizing that this could provide an affordable, one-time intervention, unlike daily medications or long-term lifestyle changes.
The intriguing link between shingles vaccination and a lower dementia risk is significant for a few reasons. It underscores the effectiveness of “natural studies,” which utilize extensive observational data; it highlights how repurposing existing vaccines can yield new solutions in areas where new drugs may falter; it suggests a role for viruses in neurodegenerative conditions; and it sheds light on broader benefits of vaccination, especially at a time when public faith in such measures is shaky.
Most research has concentrated on the Zostavax vaccine, a live vaccine that uses an attenuated form of the varicella-zoster virus. Although this vaccine has largely been replaced by the more effective Shingrix in many countries, it remains relevant for this discussion. The virus responsible for childhood chickenpox can later reactivate, leading to shingles, which can have serious long-term consequences, especially for older adults or those with weakened immune systems.
In 2013, Wales launched a program to vaccinate individuals between 70 and 79 years old. Those who turned 80 after a particular cutoff date couldn’t receive the vaccine, creating an interesting comparison group. As Geldsetzer pointed out, this provided a unique opportunity: comparing people born just a week apart meant the only significant difference was their chance of getting vaccinated.
Over the next seven years, nearly 280,000 individuals in these two groups revealed a notable difference: the vaccinated group was 20% less likely to receive a dementia diagnosis. Eric Topol, a researcher based in the US, reviewed the findings and noted that if this vaccine were a drug that reduced Alzheimer’s cases by that margin, it would be seen as a breakthrough. A recent study even hinted at a connection between the vaccine and slower biological aging.
The reasons behind the disparity between men and women in vaccine benefits remain unclear, as does whether the advantage stems from simply keeping the shingles virus suppressed or from a broader immune system enhancement resulting from the vaccination. Research from 2024 pointed to the Shingrix and RSV vaccines being associated with an even greater reduction in dementia risk, likely due to an immune-boosting component. There remains ambiguity regarding individuals who have already experienced shingles and whether vaccination would benefit them.
Geldsetzer aims to secure funding for a clinical trial on Zostavax to address these unanswered questions and move towards regulatory approval. Additionally, the Alzheimer’s Society and researchers at the University of Exeter recently identified Zostavax as a worthwhile candidate for further investigation.
Meanwhile, the UK has announced a decision to lower the eligibility age for the Shingrix vaccine to 60. The UK Health Security Agency noted that vaccine advisors consider potential off-target benefits and acknowledge this significant link. Topol suggests that individuals over 50 should contemplate getting vaccinated. With Zostavax now off patent, one can only hope this relatively affordable vaccine—potentially having far-reaching consequences for patients and future dementia research—is worth the attention it’s getting.
