For years, scientists have known there was a strange connection between shingles and dementia, but no one could say for sure whether one actually influenced the other. Now, several major studies are providing the strongest evidence yet that the shingles vaccine may do more than prevent a painful rash, it could also help protect your brain.
Shingles is caused by the herpes zoster virus, the same virus responsible for chickenpox. After a person recovers from chickenpox, the virus remains dormant in the nervous system and can reactivate decades later as shingles. Researchers have long suspected that herpes viruses may contribute to the inflammation and amyloid beta plaque buildup associated with Alzheimer’s disease and other forms of dementia.
The biggest breakthrough came from a series of “natural experiments” in Wales. When the country introduced its shingles vaccination program in 2013, eligibility was determined by age, creating two otherwise similar groups of older adults: one with access to the vaccine and one without. After following participants for seven years, researchers found that those who received the vaccine had significantly lower rates of dementia. Follow-up studies in Australia and the United States reached remarkably similar conclusions, strengthening the evidence that the association is real.
The research gets even more interesting. Scientists also found that people who received the shingles vaccine after being diagnosed with dementia experienced fewer dementia-related deaths over the following nine years. While the vaccine isn’t a cure, the findings suggest it may slow the progression of the disease as well as reduce the risk of developing it in the first place.
Researchers are still working to understand exactly why this happens. One leading theory is that preventing the shingles virus from reactivating also prevents the chronic inflammation and biological changes that contribute to cognitive decline. Another possibility, that vaccines simply boost the immune system in general, appears less likely after researchers compared the shingles vaccine to the pneumonia vaccine and found that only the shingles vaccine was associated with a significantly lower risk of dementia.
While more research is needed before doctors can recommend the shingles vaccine specifically as a dementia prevention strategy, the evidence continues to grow. Considering how safe, affordable, and widely available the vaccine already is, it may one day prove to be one of the simplest tools we have for protecting not just our bodies, but our minds as well. If you’d like to dive deeper into the science behind these surprising findings, check out the SciShow video below, which breaks down the latest research and explains why scientists are so excited about the potential link between shingles vaccination and a lower risk of dementia.