BCG vaccine may offer low-cost strategy to prevent Alzheimer’s disease, study finds
HYDERABAD: The century-old Bacillus Calmette-Guérin (BCG) vaccine, widely used to protect against tuberculosis, may offer a low-cost way to help prevent Alzheimer’s disease, according to an exploratory clinical study published in the peer-reviewed journal Communications Medicine, as reported by Deccan Chronicle.
The one-year study found that the vaccine reprogrammed the brain’s immune system and improved several Alzheimer’s-related biomarkers. Researchers say the findings suggest BCG, one of the world’s oldest and safest vaccines, could become an affordable preventive option if larger clinical trials confirm the results.
Researchers conducted the open-label study on 23 adults aged 55 and above at a single centre in the United States. Twelve participants showed no Alzheimer’s-related brain changes, while 11 had biomarkers linked to the disease. None had previously received the BCG vaccine or had a tuberculosis infection.
The team gave each participant two intradermal doses of the vaccine one month apart. They monitored safety, memory, thinking abilities, immune responses, and Alzheimer’s biomarkers in blood and cerebrospinal fluid for one year.
The vaccine triggered long-lasting “trained immunity”-like responses in immune cells found in the cerebrospinal fluid. Researchers said this is the first clinical evidence that the brain’s immune system can be reprogrammed for a prolonged period in living humans.
Participants without established Alzheimer’s-related changes also showed favourable improvements in amyloid-beta biomarkers. The vaccine was well tolerated, and researchers reported no unexpected safety concerns.
However, the team stressed that larger randomised controlled trials must confirm these findings before doctors can recommend BCG as a preventive treatment for Alzheimer’s disease.
India could play a key role
Speaking to the media, Mahesh Chandra Kodali, Senior Research Fellow in the Department of Neurology at Harvard Medical School and Massachusetts General Hospital, said the findings could be especially important for India because of its universal BCG vaccination programme and rapidly ageing population.
“India has a unique opportunity because BCG is already part of the country’s healthcare system. It is a low-cost vaccine with an excellent safety record and has protected millions of Indians for decades. If larger clinical trials confirm these findings, BCG could become a much more affordable and accessible option than many current Alzheimer’s treatments,” Kodali said.
He said the study achieved two major advances. First, it showed that BCG can reprogramme the brain’s immune system. Second, the researchers developed a functional test that measures how immune cells surrounding the brain respond using cerebrospinal fluid.
“Until now, researchers had no way to measure how these immune cells function in living patients. This method could help doctors detect immune problems earlier, track disease progression, and determine whether treatments are changing immune function in the brain,” he said.
Kodali added that the new technology could speed up research on Alzheimer’s disease and several other neurological disorders. He also urged India to launch a multicentre clinical trial. He said the country is well placed to answer globally important questions about BCG’s potential role in preventing dementia.
