BCG is a vaccine which is given to children under 12 months to protect them from tuberculosis (TB). It is very effective but even people who have been vaccinated can get the disease. BCG in full is Bacillus Calmette-Guerin: BACILLUS is Latin for bacteria. CALMETTE and GUERIN are the names of the French researchers who invented the vaccination.
Attribution: Straight Talk Foundation & Marie Stopes