Recent research suggests that shingles vaccines might not only prevent the painful rash associated with the virus but could also offer a benefit to cognitive health, potentially reducing the risk of dementia.
The varicella-zoster virus, responsible for both chickenpox and shingles, affects nearly 98% of adults in the United States. This virus can remain dormant in nerve roots and reactivate under stress or when immunity is compromised, leading to shingles—a condition characterized by a painful rash that can persist for weeks.
Emerging evidence indicates that herpes viruses, including varicella-zoster, may also reside in the brain and reactivate, potentially contributing to dementia. Although no cure for shingles exists, antiviral treatments and vaccines are available. The first shingles vaccine, Zostavax, was approved in 2006, followed by a more potent version, Shingrix, in 2017. The Centers for Disease Control and Prevention (CDC) now recommends Shingrix over Zostavax for individuals aged 50 and older due to its higher efficacy and longer-lasting protection.
Recent studies have investigated the potential cognitive benefits of Shingrix. Two significant studies analyzed the medical records of hundreds of thousands of individuals who received Shingrix and compared their dementia diagnoses to those who received other vaccines.
The first study, published in Nature Medicine, examined over 200,000 adults aged 65 and older, comparing Shingrix and Zostavax recipients. Researchers found that individuals who received Shingrix had a 17% lower risk of developing dementia within six years compared to those who received Zostavax. While the study does not definitively prove a causal relationship, it suggests a delay in dementia onset for Shingrix recipients, averaging an additional 164 diagnosis-free days.
This study’s findings align with a growing body of evidence suggesting that shingles vaccines could be beneficial for brain health. Dr. Andrew Doig from the University of Manchester notes that the newer Shingrix vaccine might offer an even greater reduction in dementia risk compared to its predecessor. Women, in particular, showed a 22% lower risk of developing dementia compared to 13% for men.
Additionally, when comparing Shingrix with flu and diphtheria-pertussis-tetanus (tDAP) vaccines, Shingrix recipients had a 23% lower risk of dementia compared to those who received a flu shot and a 28% lower risk compared to tDAP recipients.
The second study, set to be presented at the Alzheimer’s Association International Conference, echoes these findings. This research, sponsored by GSK and utilizing data from nearly 600,000 patients, found that Shingrix was associated with a 20% lower likelihood of dementia diagnosis compared to Pneumovax, a vaccine for bacterial infections. The study also indicated a 23% reduced risk for Shingrix users compared to Zostavax recipients after five years.
Despite these promising results, researchers emphasize that further investigation is needed to confirm the shingles vaccine’s impact on dementia risk. Dr. Phil Dormitzer of GSK advises that while these findings are significant, they are preliminary and should not yet prompt changes in vaccine usage.
For now, the primary motivation for receiving a shingles vaccine remains the prevention of shingles itself.
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