PROVIDENCE, R.I. (WOWO) — A shingles vaccine used routinely in older adults is being linked to a significantly lower risk of dementia, according to a large new study led by Brown University researchers. The study, published in the Annals of Internal Medicine, found adults 66 and older who received at least one dose of the recombinant shingles vaccine, known by the brand name Shingrix, had a 24% lower relative risk of being diagnosed with dementia over four years than people who did not receive the vaccine. Researchers analyzed Medicare claims and electronic health records involving 509,926 people admitted to more than 5,500 skilled nursing facilities across the United States between 2017 and 2022. The study population was made up of older adults who were eligible for the shingles vaccine and did not have a prior dementia diagnosis. The numbers were notable: 18.8% of people who received Shingrix developed dementia during the four-year follow-up, compared with 24.6% of those who remained unvaccinated. Researchers said that difference translates to approximately one dementia case potentially prevented for every 17 people vaccinated. The findings are particularly significant because earlier research linking shingles vaccination with dementia risk often examined Zostavax, an older shingles vaccine that has since been replaced in the United States by Shingrix. “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,” study author Kaley Hayes, an assistant professor at Brown University’s School of Public Health, said in a university release. Hayes said the findings add to a growing body of evidence examining whether vaccines might have effects beyond preventing the infections they were designed to target. “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,” Hayes said. The researchers used a statistical technique called target-trial emulation, which is intended to replicate some of the characteristics of a randomized clinical trial when an actual trial is not feasible. Despite the size of the study, researchers stress that it was observational. That means the findings demonstrate an association between Shingrix vaccination and lower dementia diagnoses — not proof that the vaccine itself prevents dementia. People who received the vaccine were somewhat younger and healthier than those who did not, according to Brown University. Researchers adjusted their analysis for those differences, but said additional research, including clinical trials, is needed to determine whether vaccination directly reduces dementia risk. That distinction was also emphasized by Dr. Ajeet Sodhi, a clinical neurologist and neuro-interventionalist who was not involved in the Brown research. “This is maybe the third or fourth study, and they all came to the same conclusion,” Sodhi told Fox News Digital. Sodhi described the findings as “remarkable,” while cautioning that Shingrix is not currently considered a treatment for dementia. “It’s not at this time considered a treatment,” Sodhi said. “This association is … very, very suggestive, but we can’t say one-to-one it proves that this treats dementia.” Scientists do not yet know precisely why people who receive the shingles vaccine appear to have a lower risk of dementia. One possibility involves the disease the vaccine is designed to prevent. Shingles is caused by the varicella-zoster virus, the same virus that causes chickenpox. After someone recovers from chickenpox, the virus can remain dormant in the body’s nerve tissue and later reactivate, sometimes decades afterward, causing shingles. The illness can produce a painful rash and can result in long-term complications, including postherpetic neuralgia, a form of persistent nerve pain that can continue after the rash disappears. Researchers have also been examining connections between shingles, inflammation and vascular problems. Hayes told MedPage Today that one potential explanation is that preventing shingles could reduce neuroinflammation and lower the risk of stroke, which itself can contribute to cognitive impairment. Another possibility being investigated is whether some vaccines could have broader effects on the immune system that ultimately benefit brain health. Sodhi also pointed to research examining possible cardiovascular and cerebrovascular benefits associated with shingles vaccination, including potential reductions in heart attacks and strokes. For now, however, the established purpose of Shingrix remains protection against shingles and its complications. The Centers for Disease Control and Prevention recommends a two-dose Shingrix series for adults 50 and older. The vaccine is also recommended for adults 19 and older who are, or will be, immunocompromised because of disease or treatment. The vaccine was introduced in 2017 and is currently the only shingles vaccine available in the United States, according to Brown University. The new research found that relatively few people in the study population received Shingrix during the period examined. Only 8,843 of the more than 509,000 participants received at least one dose. Researchers acknowledged another potential limitation known as “vaccine bias,” in which people who choose to receive vaccinations may differ in important ways from those who do not. Those underlying differences can make it difficult to determine whether the vaccine itself is responsible for an observed health benefit. The study was funded in part by GlaxoSmithKline, the manufacturer of Shingrix. Brown researchers said GSK had no control over the study’s design, analysis or decision to publish the results. The latest findings nevertheless add to a series of studies that have raised questions about whether preventing shingles could have consequences for long-term brain health. For older adults, experts say the dementia findings should be viewed as an additional research development — not a substitute for established dementia prevention, diagnosis or treatment. Sodhi also urged people experiencing memory problems or noticing cognitive changes to seek medical attention rather than waiting for symptoms to become more severe. “The common theme in all of this is the sooner you seek evaluation, the better it is for the treatment,” Sodhi told Fox News Digital. He said treatment is more likely to be effective when cognitive disease is identified earlier. For now, the 24% figure represents an association observed in a large population — and researchers say determining whether Shingrix itself is responsible will require further investigation. The post Shingrix Linked to 24% Lower Dementia Risk in Older Adults, Study Finds appeared first on WOWO News/Talk 92.3 FM and 1190 AM. ...read more read less