How does vaccination for tuberculosis prevents a person from getting the disease?

Vaccination for tuberculosis (TB), primarily using the Bacillus Calmette-Guérin (BCG) vaccine, helps to prime the immune system to recognize and fight the Mycobacterium tuberculosis bacteria. While it may not prevent infection entirely, it significantly reduces the risk of developing severe forms of TB, especially in children. The vaccine stimulates an immune response that prepares the body to respond more effectively if exposed to the bacteria in the future. This proactive defense mechanism is crucial in controlling the spread of TB in populations.