Alzheimer’s disease, a devastating form of dementia, affects millions of people around the world.
It slowly takes away memory and thinking skills, leaving families with heartbreak and few treatment options.
But a surprising discovery may offer a new path forward—using an old vaccine originally meant to fight tuberculosis.
The BCG vaccine has been around for nearly a century. It’s mainly used to prevent tuberculosis, a serious lung infection, and is also used to treat a type of bladder cancer.
But researchers have now found it might have another unexpected benefit: protecting the brain from Alzheimer’s.
A team of scientists from Massachusetts General Hospital and Brigham and Women’s Hospital followed 6,467 bladder cancer patients over a period of up to 15 years. About half of them received the BCG vaccine as part of their cancer treatment; the other half did not.
Here’s what they found: only 202 people who got the vaccine later developed Alzheimer’s or a related disease, compared to 262 people who didn’t receive the vaccine.
That means those who had the BCG shot were about 20% less likely to develop Alzheimer’s. Even more encouraging, this protective effect was strongest in people aged 70 and older. On top of that, the vaccine group also had a 25% lower risk of dying during the study.
This finding is surprising—but also exciting. Dr. Marc Weinberg, one of the lead researchers, called it “a potentially affordable way to fight a terrible disease.”
Unlike new drugs that can take decades and millions of dollars to develop, the BCG vaccine is already available and widely used. If it turns out to truly help prevent Alzheimer’s, it could become an accessible option for millions of older adults.
Why might this vaccine help the brain? Scientists think it may “train” the immune system in a unique way. The idea is that the BCG shot may reduce harmful inflammation or boost protective immune responses, which might keep the brain healthier over time.
Of course, more research is needed. The current study looked at people who got the vaccine as part of bladder cancer treatment, not as a general population prevention method. That’s why the researchers are now planning special clinical trials to give the BCG vaccine to older adults without cancer, to see if it truly lowers the risk of Alzheimer’s in a wider group.
If future studies confirm these results, this decades-old vaccine could offer a powerful and affordable tool in the fight against one of the world’s most challenging brain diseases.
The study was published in JAMA Network Open.
If you care about Alzheimer’s, please read studies about the likely cause of Alzheimer’s disease , and new non-drug treatment that could help prevent Alzheimer’s.
For more information about brain health, please see recent studies about diet that may help prevent Alzheimer’s, and results showing some dementia cases could be prevented by changing these 12 things.
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