Researchers have found that patients treated with the Bacillus Calmette-Guérin (BCG) vaccine may have a reduced risk of Alzheimer’s disease and related dementias, according to a novel study published by Weinberg et al in JAMA Network Open.
Background
The BCG vaccine has been known to offer multiple beneficial effects—including the prevention of tuberculosis—and is currently a recommended therapy for patients with non–muscle-invasive bladder cancer.
Although previous studies have suggested that the BCG vaccine may be inversely associated with the risk of dementia, these studies were limited by size, design, or analytical methods.
Study Methods and Results
In the new study, the researchers analyzed the outcomes of 6,467 patients with non–muscle-invasive bladder cancer—3,388 of whom received the BCG vaccine and 3,079 of whom were controls.
After a follow-up of 15 years, the researchers discovered that 202 of the patients who received the BCG vaccine and 262 controls developed Alzheimer’s disease and related dementias. The incidence was 8.8 per 1,000 person-years and 12.1 per 1,000 person-years in the respective groups. The researchers revealed that treatment with the BCG vaccine was associated with a 20% lower risk of Alzheimer’s disease and related dementias. Further, the preventive effects were greater in patients aged 70 years and older. The researchers also found that 751 patients in the BCG vaccine group and 973 in the control group died, demonstrating that the BCG vaccine may be associated with a 25% decreased risk of death.
Conclusions
“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,” highlighted lead study author Marc Weinberg, MD, PhD, Professor of Psychiatry at Harvard Medical School and a physician in the Department of Psychiatry and Neurology at Massachusetts General Hospital. “We are shifting our focus toward studying the potential benefits of BCG vaccination [in] older adults [through] Alzheimer’s disease–related clinical trials.”
Dr. Weinberg and his colleagues concluded that if a causal link is found, they will seek to more fully understand the mechanisms involved and whether the BCG vaccine’s effects on the immune system may play a role.
Disclosure: The research in this study was supported by the National Institutes of Health and the Alzheimer’s Association. For full disclosures of the study authors, visit jamanetwork.com.
