December 10, 2025
The shingles vaccine may provide benefits to people who have dementia, by slowing the progression of disease, a new study suggests. The study is a follow-up to an earlier report from Stanford researchers that found that getting vaccinated against shingles may lower the risk of developing Alzheimer’s disease and other forms dementia years down the road.
Most of us were infected with the virus that causes chickenpox as children. The virus then lies dormant in nerve roots for decades. As we age and our immune systems weaken, the virus can be reactivated, causing the painful skin blisters of shingles. The shingles vaccine, recommended for people 50 and older, is highly effective in preventing or limiting virus reactivation and subsequent shingles outbreaks.
In an earlier analysis, the Stanford research team looked at the rollout of the shingles vaccine in 2013 among elderly men and women in Wales. Because of limited vaccine supplies, only some of the seniors were vaccinated against shingles, based on age at the start of the program. By comparing those who were vaccinated with those who were not, the researchers found that, over the next seven years, vaccination not only decreased the risk of having a shingles outbreak, it also reduced the risk of developing dementia by about 20 percent. The study provided some of the strongest evidence to date that the virus that causes shingles may be related to Alzheimer’s disease.
In their new analysis, the Stanford researchers found that vaccination may help prevent mild cognitive impairment, a brain disorder that often progresses to full-blown Alzheimer’s. Vaccinated individuals were less likely to be diagnosed with mild cognitive impairment within nine years of vaccination.
The shingles vaccine also appeared to have benefits for those who already had Alzheimer’s disease or another form of dementia. People who received the vaccine after a dementia diagnosis were significantly less likely to die from dementia over the next nine years, suggesting that the vaccine could slow the progression of the disease. Overall, of the 7,049 Welsh seniors who had dementia at the start of the vaccination program, nearly half died from dementia (as determined by their death certificate) during the follow-up period; but among those who’d been vaccinated, only about 30 percent died from dementia. The protective effects of the vaccine were particularly pronounced in women.
“The most exciting part is that this really suggests the shingles vaccine doesn’t have only preventive, delaying benefits for dementia, but also therapeutic potential for those who already have dementia,” said Dr. Pascal Geldsetzer, the study’s senior author and an assistant professor of medicine at Stanford.
Scientists aren’t sure why shingles might lead to cognitive decline or slow progression of dementia. The chickenpox virus that causes shingles, varicella zoster, has been linked to an increased risk of heart disease and stroke, both risk factors for dementia. Some research suggests the virus may also damage the lining of blood vessels, including those in the brain, or damage nerve cells directly. Infections may also increase brain inflammation, which may play a role in dementia onset. By limiting the severity of infections, vaccines may reduce brain inflammation.
More research is needed to better understand how viruses such as varicella zoster might contribute to the onset of Alzheimer’s disease. In the meantime, the shingles vaccine, known as Shingrix, is recommended for adults 50 and older. It is given in two doses, two to six months apart. Vaccination may cause some soreness for a day or two at the injection site, but over the long run, it may help prevent a painful outbreak of shingles and possibly keep the brain in good working order as well.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Stanford Medicine. Min Xie, Markus Eyting, Christian Bommer at al: “The effect of shingles vaccination at different stages of the dementia disease course.” Cell, December 2, 2025
