Many older adults face risks from both shingles and dementia. A recent analysis found that older people who received the recombinant shingles vaccine (RZV, also called Shingrix) were less likely to be diagnosed with dementia within four years after entering skilled nursing care.
The researchers analyzed Medicare claims and electronic health records for more than 500,000 adults admitted to over 5,500 skilled nursing facilities across the country between 2017 and 2022. They compared people who had at least one dose of RZV with those who did not; the vaccine was introduced in 2017 and is currently the only shingles vaccine on the market. In the study, 8,843 of 509,926 participants received the vaccine.
Key results include the following:
- After four years, 18.8% of vaccinated adults developed dementia.
- By comparison, 24.6% of unvaccinated adults developed dementia.
- The vaccinated group had a 24% lower risk of a dementia diagnosis, which the authors estimate could equal about one in 17 cases potentially prevented.
The team used a target trial emulation method to approximate a randomized clinical trial when a trial was not practical. Authors came from Brown University, the University of Delaware, the Providence Veterans Affairs Medical Center and other institutions, and the paper appears in Annals of Internal Medicine. The researchers caution that they cannot prove causation: vaccinated people tended to be slightly younger and healthier, and although the team adjusted for those differences the association was not fully explained. The authors also disclosed funding from GlaxoSmithKline, which makes Shingrix, and said the company had no control over study design, analysis, or the decision to publish. More research, including clinical trials, will be needed to determine whether the vaccine directly reduces dementia risk.
Difficult words
- dementia — progressive loss of memory and thinking abilities
- recombinant — made by combining genetic material in laboratory
- skilled nursing facility — residential healthcare place for people needing daily nursingskilled nursing facilities
- electronic health record — digital files of patients' medical informationelectronic health records
- vaccinate — to give a vaccine to prevent diseasevaccinated
- adjust — to account for other factors in an analysisadjusted
- causation — a relationship where one thing directly causes another
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- What further research would you consider most important to test whether the vaccine reduces dementia risk, and why?
- How might differences in age and overall health between vaccinated and unvaccinated people affect study results? Give an example.
- If a vaccine were shown to lower dementia risk, how could that affect decisions by older adults or care facilities?
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