New Evidence Suggests Therapeutic Benefits
A major new study has found that the shingles vaccine may do more than prevent a painful viral outbreak. According to research published Tuesday in Cell, the two-dose shingles shot appears to slow the progression of dementia and reduce the risk of dying from the disease. The findings build on earlier work suggesting that the vaccine may help prevent or delay dementia before it develops.
“We see an effect on your probability of dying from dementia among those who already have dementia,” said Dr. Pascal Geldsetzer, senior author of the study and an assistant professor at Stanford University. “That means the vaccine doesn’t just have a preventive potential, but actually a therapeutic potential.”
Large Data Sets in Wales and Australia Strengthen Findings
Researchers examined the health records of more than 282,500 older adults in Wales, taking advantage of a unique eligibility rule in the country’s shingles vaccination program. Adults who were 79 when the program began in 2013 qualified for vaccination, while those who were 80 did not. This natural age cutoff created two almost identical groups with dramatically different vaccination rates.
Among adults with no prior history of cognitive impairment, receiving the shingles vaccine reduced the likelihood of developing mild cognitive impairment by 3.1 percentage points over nine years. The protective effect appeared to be stronger in women. A similar analysis of Australian health records showed comparable outcomes.
Perhaps the most striking finding came from adults already diagnosed with dementia. Those who received the shingles vaccine had a 29.5 percentage point reduction in the risk of dying from dementia across nine years compared with unvaccinated peers.
Why Might a Shingles Vaccine Influence Brain Health?
The study did not pinpoint a definitive biological mechanism, but the researchers outlined two likely explanations. First, the varicella zoster virus remains in the nervous system after childhood chickenpox, periodically reactivating and causing inflammation. Vaccination reduces these reactivations, limiting inflammation that could accelerate dementia.
The second theory centers on the vaccine’s broader immune benefits. “There’s increasing evidence that vaccines have broader effects on the immune system,” Geldsetzer said. Stronger immunity may reduce the risk of infections linked to dementia progression.
Outside experts say the findings are compelling but not conclusive. Dr. Angelina Sutin of Florida State University said the study offers “the closest to causal evidence” available without a randomized trial. Dr. Joel Salinas of NYU Langone cautioned that the data may not fully apply to newer shingles vaccines now in use.
What Comes Next?
Geldsetzer and colleagues hope to secure funding for a randomized clinical trial, which would provide definitive evidence of whether the shingles vaccine can slow cognitive decline. In the meantime, experts encourage older adults to talk with their doctors about vaccination.
“When people ask how to keep their brain healthy, I tell them to exercise, stay social and pursue activities they enjoy,” Sutin said. “Now I will add: talk to your doctor about the shingles vaccine.”