A recent study has unveiled an intriguing connection between Shingrix, a new vaccine designed to protect against shingles, and a delay in the onset of dementia. This finding builds on earlier research that indicated a similar benefit from the older shingles vaccine, Zostavax.
Researchers from the United Kingdom, in a study published in Nature Medicine, discovered that Shingrix could delay dementia onset by 17% compared to Zostavax. The team analyzed data from electronic health records, comparing 103,837 people who received Zostavax (between October 2014 and September 2017) with 103,837 who received Shingrix (between November 2017 and October 2020). They found that those who received Shingrix had an average of 164 extra days without a dementia diagnosis during the follow-up period.
Shingles, caused by the varicella-zoster virus, primarily affects older adults, leading to painful rashes. Zostavax, the older vaccine, provided good protection for about five years with a single shot. Shingrix, based on newer technology, offers stronger and longer-lasting protection and is administered in two doses. It has replaced Zostavax in national immunization programs in Australia and elsewhere since November 2023, providing free vaccinations to high-risk groups.
Comparing Shingrix to other vaccines, including those for influenza and a combined vaccine for tetanus, diphtheria, and pertussis, researchers found that Shingrix and Zostavax performed significantly better in lowering dementia risk. The benefits were particularly notable for women, who have a higher genetic and hormonal risk for dementia.
Why the Link?
The connection between vaccines and reduced dementia risk has been noted for over two decades. It’s thought that preventing viral infections, like shingles, could indirectly reduce dementia risk. Viral infections such as herpes, closely related to the shingles-causing varicella-zoster virus, have been linked to higher dementia risk. Shingles itself has also been associated with an increased risk of later dementia diagnosis.
Two potential pathways might explain why infections could increase dementia risk:
•Molecular Reactivation: Molecules produced during fetal development that cause inflammation and aging are usually silenced at birth. Viral infections like shingles can reactivate these molecules in adults, potentially leading to dementia.Protein Interaction: In Alzheimer’s disease, rogue Amyloid-<0xCE><0xB2> proteins kill brain cells. Proteins produced by viruses and harmful gut bacteria can support these toxic forms, accelerating dementia onset.Implications and Future Research.
As the population ages, the burden of dementia will likely grow. While the study suggests Shingrix may have a silent benefit in delaying dementia, more research is needed to understand the full implications. This study highlights the importance of exploring how infections are linked with dementia, potentially guiding future therapies and prevention strategies.
The study offers hope that Shingrix, beyond its role in preventing shingles, might also contribute to delaying dementia. As researchers delve deeper into the relationship between viral infections and brain health, we move closer to unraveling the mysteries of dementia and finding ways to combat this debilitating condition.
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