BCG Vaccine May Impact Alzheimer's Markers

Mass General Brigham researchers have published new findings in *Communications Medicine* indicating that the Bacillus Calmette‑Guérin (BCG) vaccine, traditionally used to prevent tuberculosis, may alter the immune landscape of the human brain. The study shows that BCG delivered through the skin can remodel microglial activity and other neuroimmune components, potentially creating an environment that reduces the risk of Alzheimer’s disease.

The investigators examined brain tissue and immune markers in vaccinated individuals, noting changes in cytokine profiles and microglial activation states that align with mechanisms known to protect against neurodegeneration. These observations provide a biological basis for epidemiological studies that have linked early‑life BCG vaccination with lower incidence of Alzheimer’s, suggesting that the vaccine’s influence extends beyond its anti‑tuberculosis effects.

If confirmed in larger, longitudinal studies, the research could inform new preventive strategies for Alzheimer’s disease and highlight the broader neurological impacts of vaccines traditionally considered for infectious disease control.