Old Vaccine Associated with a Significantly Lower Rate and Risk of Alzheimer Disease and Related Dementias

A recent study conducted in Boston, MA, found patients appear to live longer and have a reduced incidence of Alzheimer's disease and related dementias (ADRD) after BCG vaccine treatment. 

This Original Investigation was published by the peer-review journal The JAMA Network Open on May 19, 2023, and found the 100-year-old Bacillus Calmette-Guérin (BCG) vaccine was associated with a reduced risk of Alzheimer's disease and related dementias.

Led by investigators at Massachusetts General Hospital (MGH) and Brigham and Women's Hospital (BWH), this study's analyses revealed that treatment with the BCG vaccine was associated with a 20% lower risk of Alzheimer's disease and related dementias.

The protective association was more significant in patients aged 70 years or older.

Additionally, 751 patients in the BCG vaccine group and 973 in the control group died during follow-up.

Thus, treatment with BCG vaccine was associated with a 25% lower risk of death.

"A vaccine like BCG, if proven effective, is a perfect example of a cost-effective, population-health–based solution to a devastating illness like Alzheimer's disease," stated Marc Weinberg, MD, Ph.D., an Instructor in Psychiatry at MGH, in a press release on May 19, 2023. Clinical trials are required to study its efficacy beyond treatment in patients with bladder cancer.

"We are shifting our focus towards studying the potential benefits of BCG vaccination of older adults in Alzheimer's disease-related clinical trials."

If a causal link is found, it will be important to understand the mechanisms involved.

Weinberg and his colleagues note that the BCG vaccine's effects on the immune system may play a role.

The BCG vaccine is an attenuated, live culture preparation of the BCG strain of Mycobacterium Bovis. The initial BCG vaccine was developed in 1921 by French scientists Albert Calmette and Camille Guérin.

Various BCG vaccines are integrated into pediatric vaccination schedules in multiple countries (Africa, Brazil, India, the U.K., etc.) primarily to reduce the risk of tuberculosis.

However, in the U.S., access to the BCG vaccine is limited to reducing tuberculosis risks, says the U.S. CDC.

Recently, BCG vaccinations have been associated with treating a type of bladder cancer.

Additional co-authors include Sun Young Chung, BS; Wesley H. Chou, MD; Madhur Nayan, MD, Ph.D.; Mayuresh Deodhar, MS; Daniel M. Frendl, MD, Ph.D.; Adam S. Feldman, MD, MPH; Denise L. Faustman, MD, Ph.D.; Steven E. Arnold, MD; and Bella Vakulenko-Lagun, Ph.D.

This work was supported by the National Institutes of Health and the Alzheimer's Association.