Shingles Vaccine Tied to 24% Lower Dementia Risk in Nursing Home Study

Older adults who received a shingles vaccine after entering a skilled nursing facility were less likely to be diagnosed with dementia over the following four years, according to a new study published in the journal Annals of Internal Medicine. Researchers compared patients who received at least one dose of the recombinant shingles vaccine, known as RZV or Shingrix, with patients who remained unvaccinated, and found that the vaccinated group had a 24% lower risk of dementia.

The study drew on Medicare claims and health records from 509,926 adults aged 66 and older who were admitted to more than 5,500 skilled nursing facilities nationwide between 2017 and 2022. Only 8,843 of them received the shingles vaccine. Dementia developed in 18.8% of vaccinated participants over four years of follow-up, compared with 24.6% of those who were not vaccinated — a difference that lead author Kaley Hayes, an assistant professor at Brown University, said translates to about one in 17 dementia cases potentially being prevented.

The results are consistent with several earlier studies that found a similar association using an older shingles vaccine, Hayes said. "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," she said. Shingrix, introduced in 2017, is currently the only shingles vaccine available on the market.

The study cannot prove that the vaccine itself caused the lower dementia rate. People who received it tended to be slightly younger and healthier than those who did not, differences that could also lower dementia risk; the researchers adjusted their analysis for these factors and found they did not fully explain the association. The authors say additional research, including clinical trials, is needed to establish whether shingles vaccination directly reduces dementia risk. Hayes and colleagues from Brown, the University of Delaware and the Providence Veterans Affairs Medical Center reported receiving funding from GlaxoSmithKline, the maker of Shingrix, which they said had no control over the study's design, analysis or the decision to publish.