How is bcg caused?

BCG, or Bacillus Calmette-Guérin, is a vaccine primarily used against tuberculosis. It is caused by the administration of a live attenuated strain of Mycobacterium bovis, which is related to the bacterium that causes TB. The vaccine stimulates the immune system to recognize and respond to the bacteria, providing protection against tuberculosis infections. It can also be used in some cases to treat bladder cancer, leveraging the immune response for therapeutic effects.