BCG vaccine reduces the risk of Alzheimer’s disease

A recent study suggests that the Bacillus Calmette-Guerin (BCG) vaccine, a 100-year-old tuberculosis vaccine, may potentially reduce the risk of Alzheimer’s disease and related dementias. The BCG vaccine is currently used as a recommended treatment for non-muscle-invasive bladder cancer.

Published in JAMA Network Open, the study found that individuals treated with the BCG vaccine had a 20% lower risk of developing Alzheimer’s disease and related dementias. The protective effect was more pronounced in patients aged 70 years or older and also showed a reduced risk of death.

The research, conducted by Massachusetts General Hospital (MGH) and Brigham and Women’s Hospital (BWH), followed 6,467 individuals diagnosed with non-muscle-invasive bladder cancer for up to 15 years. Among the participants, 3,388 received the BCG vaccine treatment, while 3,079 served as control subjects, matched for age, sex, and medical conditions.

During the follow-up period, 202 patients in the BCG vaccine group and 262 in the control group developed Alzheimer’s disease and related dementias. The incidence rates were 8.8 per 1,000 person-years and 12.1 per 1,000 person-years, respectively.

Additionally, 751 patients in the BCG vaccine group and 973 in the control group died. Therefore, treatment with the BCG vaccine was also associated with a 25% lower risk of death.

The researchers, including Marc Weinberg from MGH, highlighted that if the causal link is established, it would be important to understand the underlying mechanisms. The effects of the BCG vaccine on the immune system may play a role. They are now focusing on studying the potential benefits of BCG vaccination in older adults through clinical trials related to Alzheimer’s disease.

It is important to note that while these findings are promising, further research is needed to establish a definitive connection between the BCG vaccine and reduced risk of Alzheimer’s disease and related dementias.