Bacillus Calmette-Guerin strain

Bacillus Calmette-Guerin (BCG) is a live, attenuated strain of Mycobacterium bovis, a bacterium closely related to the causative agent of tuberculosis. This attenuated strain has been weakened to the point where it no longer causes disease in humans, but retains its immunogenic properties. BCG is primarily used as a vaccine for the prevention of tuberculosis, specifically the childhood form of the disease known as disseminated tuberculosis.
The vaccine stimulates the immune system to recognize and fight off the pathogenic Mycobacterium tuberculosis, thereby providing protection against the disease. BCG is also used off-label for the treatment of certain types of bladder cancer, as the live bacteria can stimulate the immune system to attack the cancer cells.
BCG is a live vaccine, and it should not be administered to individuals with compromised immune systems or certain pre-existing conditions, as it may cause severe infections. Additionally, the vaccine may not be 100% effective in preventing tuberculosis, but it significantly reduces the risk of developing the disease.