BCG and prospects for new vaccines against tuberculosis.

Seventy-five years have elapsed since its introduction and a renewed interest has arisen in the vaccination with bacillus Calmette-Guerin (BCG) for the prevention of tuberculosis. This interest has been motivated by the increase in tuberculosis, especially in multidrug-resistant tuberculosis. The efficacy of BCG has been questioned for decades, however, new epidemiological studies have shown a protective effect in some populations and categories at risk. Protection is more evident in the populations with a high incidence of the disease, especially against disseminated and invasive disease. The use of this vaccination is advised for specific populations based on the risk of infection and disease. However, BCG has a limited benefit. New agents produced with methods of molecular biology are supplying encouraging results in the animal model.