U.S. — A study published June 16, 2026, in the Annals of Internal Medicine indicates that shingles vaccination may prevent 1 in 17 dementia cases among U.S. nursing facility patients. Patients who received at least one dose of the shingles vaccine within a year of admission to a U.S. nursing facility exhibited a 5.8% lower risk of developing dementia over the subsequent four years.

The study analyzed health records from more than 509,000 individuals aged 66 and older who were admitted to U.S. nursing facilities between 2017 and 2022. Kaley Hayes, the lead study author, said, "That's huge." Shingles is a condition triggered by the reactivation of the varicella-zoster virus in the body. Jennifer Pauldurai, medical director of the Inova Brain Health and Memory Disorders Program, said, "Shingles, a condition triggered by the reactivation of the varicella-zoster virus in the body, can cause a 'war zone' of inflammation in the brain."

Previous research has identified a link between shingles infection and an increased risk of dementia. Timothy Chang, assistant professor of neurology at the Mary S. Easton Center for Alzheimer's Research and Care at the University of California, Los Angeles, said, "When the shingles virus is reactivated, it may trigger the accumulation of amyloid and tau in the brain, 'those bad proteins related to Alzheimer's disease.'" Pauldurai added, "When the brain is stressed or challenged with any kind of illness, underlying risks for dementia become more apparent." She also said, "We are more likely to get dementia when our brain is not as healthy as it could be, had we not gotten sick from shingles." Pauldurai noted, "It's not that the shingles vaccine itself is a 'magic pill.'"

Hayes explained, "Obviously, a reduction in oxygen to the brain is directly correlated with cognitive function." She added, "But there's a further hypothesis that even if there might not be a full replication of the virus in your body… that basically might cause some kind of micro-damage to your cerebral arteries." Chang said, "Having the vaccine remind our bodies to help improve our immunity in general — not just specifically to the vaccine — can be beneficial also to reduce neuroinflammatory processes that are going on." He added, "It's a good excuse to get the vaccine, if you were on the edge of considering it."

In the U.S., individuals 50 and older are eligible for two doses of Shingrix, the only shingles vaccine approved by the FDA. Shingrix received approval in 2017. The single-dose Zostavax vaccine, which was less effective than Shingrix, was discontinued in 2020. The CDC recommends Shingrix even for those who have previously received Zostavax, the chickenpox vaccine, or have had shingles. As of 2022, CDC records indicate approximately one-third of U.S. adults aged 50 and older, and 43.8% of those 60 and older, had received at least one dose of either shingles vaccine. Less than 2% of the nursing facility patients eligible for Shingrix in the study had received even one dose. Vaccine rates were lower for Black and Hispanic adults compared to white adults as of 2022.

Other studies have also explored the link between shingles vaccination and dementia risk. A Nature study of over 282,000 older adults in Wales found shingles vaccination was associated with a 3.5% reduced dementia risk over seven years. A study in the Journal of the American Medical Association involving more than 101,000 older adults in Australia found vaccine eligibility correlated with a 1.8% reduced dementia risk over 7.4 years. The Lancet Neurology published a study in February that linked vaccine eligibility to a 2% reduced dementia risk over 5.5 years among more than 232,000 older adults in Canada. In Hayes' research, the connection between Shingrix vaccination and reduced dementia risk was weaker among men and those who had previously received Zostavax. The Nature study on individuals in Wales showed a stronger association between Zostavax immunization and lower dementia risk among women.