Study: Shingles vaccine linked to 24% lower dementia risk
A new study found that older adults who received the Shingrix shingles vaccine after entering a skilled nursing facility were diagnosed with dementia less often over the following four years than unvaccinated peers. Researchers caution the findings do not prove the vaccine directly causes the reduced risk.
Researchers in the United States have found that older adults who received a shingles vaccine after being admitted to a skilled nursing facility had a 24% lower likelihood of being diagnosed with dementia over the following four years compared with those who remained unvaccinated. The analysis drew on Medicare data and health records covering more than 500,000 adults aged 66 and older admitted to over 5,500 skilled nursing facilities across the United States between 2017 and 2022.
Study author Kaley Hayes of Brown University's School of Public Health noted that most prior research on this topic focused on an older shingles vaccine, while this study examines only the newer recombinant vaccine, Shingrix, which has been on the market since 2017 and is currently the only shingles vaccine available.
Findings
Of the 509,926 people included in the analysis, only 8,843 received the vaccine. After four years of follow-up, dementia was diagnosed in 18.8% of vaccinated participants compared with 24.6% of unvaccinated ones. According to Hayes, this suggests that roughly one in 17 dementia cases could potentially be prevented.
The researchers used a method called target trial emulation, designed to approximate the conditions of a randomized clinical trial using observational data.
Limitations
The authors stress that the study cannot establish cause and effect. Vaccinated participants tended to be slightly younger and healthier overall, factors that could independently lower dementia risk. Although the analysis adjusted for these differences, they did not fully account for the observed association. Further research, including clinical trials, is needed to determine whether shingles vaccination directly reduces dementia risk.
The study was published in Annals of Internal Medicine. The authors reported receiving funding from GlaxoSmithKline, the maker of Shingrix, but said the company had no role in the study's design, analysis, or the decision to publish.
