A vaccine designed to prevent shingles may also be linked to a lower risk of dementia, according to a large study of older adults living in skilled nursing facilities across the United States. The study analyzed data from 509,926 adults age 66 and older who entered more than 5,500 skilled nursing facilities between 2017 and 2022. Only 8,843 received the shingles vaccine while the rest remained unvaccinated.
Participants had to be eligible for shingles vaccination and could not have previously been diagnosed with dementia. Researchers found that residents who received the Shingrix shingles vaccine were 24 percent less likely to be diagnosed with dementia during the following four years than those who did not receive the vaccine. Among vaccinated participants, 18.8 percent developed dementia, compared with 24.6 percent of those who did not receive the vaccine.
Based on those findings, the researchers estimated that about one dementia case might be prevented for every 17 people vaccinated. The research focused on Shingrix, also known as the recombinant zoster vaccine. Introduced in 2017, it is currently the only shingles vaccine available on the market.
Lead author Kaley Hayes said previous research had largely examined an older shingles vaccine. In contrast, this study evaluated the newer vaccine in an older and medically vulnerable population. To carry out the study, researchers used a method known as target trial emulation.
The approach is intended to make an observational study resemble a randomized clinical trial as closely as possible when conducting an actual clinical trial is difficult or impractical. The team analyzed Medicare claims data and electronic health records before comparing dementia rates between vaccinated and unvaccinated participants. The findings are consistent with several earlier studies that examined an older shingles vaccine and also found a link between shingles vaccination and a lower risk of dementia.
However, the researchers stressed that the findings do not prove the vaccine prevents dementia. Edmundo Rodriguez-Frias, a medical contributor of Full of Life, a recovery center in Marlton, New Jersey, told Newsweek that there can be two reasons behind this association, and they aren't mutually exclusive. He said: "First, directly: Shingles reactivates a nerve-loving virus, so controlling this will limit the potential for long-term brain inflammation as well.
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