Tuberculosis vaccines: hopes and hurdles.

Tuberculosis (TB) remains as one of the most serious public health problems worldwide. It is one of the main causes of death in poor and developing countries, especially in sub-Saharan Africa, where it may be associated with the human immunodeficiency virus (HIV). It has been estimated that one third of the world population is infected by Mycobacterium tuberculosis (Mtb), and there were about 8.7 million new TB cases, and about 1.4 million yearly deaths due to TB in 2011. DOTS is the currently used drug therapy in TB but there is non-compliance which results in emergence of resistance. Bacille Calmette Guérin (BCG), an attenuated vaccine derived from Mycobacterium bovis, is the only licensed TB vaccine, but not recommended in HIV-infected infants. There are 14 vaccine candidates that have entered clinical trials and over 35 candidates in discovery and preclinical development. Mycobacterium indicus pranii [Mw; MIP] and M. vaccae are in phase III clinical trial and the Drug Controller of India licensed MIP for human use in India.