Recently, the World Health Organization expanded programs of immunization recommended BCG at 3 months, while in many areas there is vaccination at birth, at school entry and in adolescence.
Bacillus Calmette-Guerin (BCG) vaccination is compulsory in 64 countries and recommended in others. As one third of the world's population is already infected with mycobacterium tuberculosis (TB), efficacious control of TB, one of the world's major health threats, is best achieved by a combination of chemotherapy and vaccination.
