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Scientific Frontline: Extended "At a Glance" Summary: Recombinant Shingles Vaccine (RZV) and Dementia Risk Reduction
The Core Concept: A recent pharmacoepidemiological study indicates that older adults who receive the recombinant shingles vaccine (Shingrix) exhibit a 24% lower risk of being diagnosed with dementia over a four-year period compared to unvaccinated peers.
Key Distinction/Mechanism: Unlike previous observational studies that focused on older live-attenuated vaccines, this research isolates the effects of the newer recombinant zoster vaccine (RZV) on a highly vulnerable demographic entering skilled nursing facilities. While the exact causal mechanism remains unconfirmed, researchers hypothesize the vaccine provides secondary neuroprotective benefits alongside targeted viral suppression.
Major Frameworks/Components:
- Target Trial Emulation: A statistical methodology designed to mimic the conditions and strict parameters of a randomized clinical trial using existing observational health records.
- Pharmacoepidemiology: The application of epidemiological reasoning and methods to study the uses and effects of drugs in well-defined human populations.
- Viral Immunization: The primary function of RZV, preventing the reactivation of the varicella-zoster virus.
- Neuroprotection: The hypothesized secondary outcome of the vaccine, which may help preserve cognitive function and delay the onset of dementia.
Branch of Science: Pharmacoepidemiology, Gerontology, Neurology, Immunology, and Public Health.
Future Application: The findings provide a strong foundation for dedicated randomized clinical trials to isolate the specific neuroprotective mechanisms of viral immunization, potentially integrating the RZV into standard, preventative cognitive care regimens.
Why It Matters: With statistical models suggesting the vaccine could potentially prevent one in 17 dementia cases in this demographic, the intervention presents a highly accessible, dual-purpose approach to protecting both physical and cognitive health in aging populations.
Older adults who received a shingles vaccine after a stay in a skilled nursing facility had a 24% lower risk of being diagnosed with dementia over a four-year period than those who were not vaccinated, according to a new study.
The findings are based on an analysis of health records and Medicare data from more than 500,000 adults aged 66 and older who were admitted to skilled nursing facilities for short- or long-term care. Researchers compared those who received at least one dose of the recombinant shingles vaccine, known as RZV or Shingrix, with those who did not. The vaccine was introduced in 2017 and is the only shingles vaccine currently on the market.
“A lot of previous studies with similar results focused on an older vaccine,” said study author Kaley Hayes, an assistant professor at Brown University’s School of Public Health. “This study looks at the newest vaccine only in an older, vulnerable adult population who were not up to date with shingles vaccination and are at a very clear clinical point in care: entering a skilled nursing facility.”
The findings align with several earlier studies that focused on a prior shingles vaccine and linked shingles vaccination to a lower risk of dementia.
“It fits into this large puzzle that’s just starting to come together that the vaccines are effective at preventing shingles and also appear to have neuroprotective benefits as well,” said Hayes, who is also the associate director of pharmacoepidemiology for Brown’s Center for Gerontology and Healthcare Research.
Hayes led the study published in Annals of Internal Medicine alongside colleagues from Brown, the University of Delaware, the Providence Veterans Affairs Medical Center, and other institutions.
To analyze the data, the team used a method known as a target trial emulation, which is designed to mimic the conditions of a randomized clinical trial when conducting one is not practical. The study included Medicare claims and electronic health record information from patients admitted to more than 5,500 skilled nursing facilities across the country between 2017 and 2022. Only 8,843 of 509,926 participants received the vaccine.
To be included in the study, patients could not have a prior diagnosis of dementia and had to be eligible to receive the shingles vaccine. After a four-year follow-up, the team found that people who received at least one of the two doses of Shingrix had a substantially lower risk of being diagnosed with dementia than those who did not receive the vaccine. According to the data, only 18.8% of vaccinated adults developed dementia within four years, compared with 24.6% of those who were not vaccinated.
“This translates to about 1 in 17 dementia cases potentially being prevented,” Hayes said.
The primary caveat of the study is that the researchers cannot say for certain that the vaccine was the reason that vaccinated adults developed dementia at a lower rate. People who got vaccinated, for instance, tended to be slightly younger and healthier than those who did not, which may have also lowered their dementia risk. The research team adjusted for those differences and found that those factors did not fully account for the association. More research, including clinical trials, will ultimately be needed to determine whether the vaccine directly reduces the risk of dementia.
The researchers say the results point toward a generally accessible tool that can help protect both the body and the mind.
“Our cognition is so tied to our overall health and what happens to us physically,” Hayes said. “It’s really amazing to see that something that’s supposed to prevent a physical ailment can also help keep our brain healthy, too.”
Funding: In the study, the authors acknowledged funding from GlaxoSmithKline, which makes the shingles vaccine Shingrix, noting that the company had no control over the study design, analysis, or decision to publish the results.
Published in journal: Annals of Internal Medicine
Authors: Kaleen N. Hayes, Daniel A. Harris, Kevin W. McConeghy, Lexie R. Grove, Richa Joshi, Lisa Han, H. Edward Davidson, Preeti Chachlani, Thomas A. Bayer, Mriganka Singh, Yasin Abul, Frank DeVone, and Stefan Gravenstein
Source/Credit: Brown University | Juan Siliezar
Edited by: Scientific Frontline
Reference Number: phar061626_01
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