Dementia is a progressive and irreversible disease. In a world where treatments for dementia have limited effect, prevention is key.
The Zostavax Study
In April 2025, a study from Stanford was published in Nature, a major scientific journal, analyzing public health data from Wales after the introduction of a live shingles vaccine, Zostavax, in September 2013.1
When the vaccine was rolled out, individuals who were 79 years old at that time were eligible to receive it, and those who were 78 would become eligible the following year. Those who were 80 years or older were never eligible for the vaccine. Because of the way the vaccine was introduced with strict age cut-offs for a whole population, this presented a unique opportunity for analysis similar to a large randomized controlled trial, with a treatment arm (those who received the vaccine) and a natural control arm.
The researchers focused on comparing people who had just turned 80 and didn't receive the vaccine versus people who were just still 79 and had received the vaccine and seeing if there was any difference in dementia onset in the following 7 years. In essence, these individuals were only weeks apart in age.1
Results
What the study authors found was that the 79-year-olds who received the shingles vaccine Zostavax were 20% less likely to develop dementia over a follow-up period compared to the 80-year-olds who didn't. The response was found to be stronger in women than men.
This is an impressively large reduction. This finding has reportedly been replicated in similar analyses of data from Australia, New Zealand, England, and Canada. How is the vaccine thought to be preventing dementia? More research will be needed to understand if the vaccine is helping by activating certain protective immune system effects or through reducing reactivation of the herpes zoster virus that causes shingles.1
Conclusions
In more recent years, vaccine programs have shifted to non-live vaccines such as Shingrix which are more effective at preventing shingles. We don't yet have data to know if these newer vaccines will have the same preventative effects.
If you're worried about developing dementia later in life, not to mention avoiding all the potentially serious effects of getting shingles, this vaccine may be something to consider.
References
- Eyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 Apr 2:1-9.