Tuberculosis is a global problem. About 9 million new cases of the disease are registered each year and the economic consequences of fighting this disease are very, very significant. Currently, six TB vaccines are undergoing clinical trials.

The traditional BCG vaccine was developed in the 1920s of the last century and is a culture of attenuated live bacteria. Gradually, the immunity caused by the vaccine weakens, that is to say the effectiveness of BCG vaccination decreases over time. In principle, it makes sense to reduce immunity in adolescents, which occurs after the use of other vaccines in childhood. It is easy to explain the increase in the number of tuberculosis cases between the ages of 15 and 24 and the occurrence of a peak incidence of tuberculosis at the age of 25-44 with this phenomenon. Different approaches to maintain immunity in adults include primary vaccination followed by 2-3 booster doses of the BCG vaccine in adolescence to improve the immunological effect that occurred after primary vaccination.

In developing countries, six tuberculosis vaccines are in the first phase of clinical trials, four of which are recombinant vaccines containing antigen 85 (AG85), which induces a stronger immune response, while others use micro- attenuated living organisms. In The Gambia, a new vaccine is being tested containing the antigen 85 with a modified vector based on the vaccinia virus. It is quite promising and is almost ready for the second phase of clinical research.

Two of the most promising vaccines are the multivalent vaccines produced by Intercell Smart Vaccines (Vienna, Austria) and Chiron Vaccine International (Novartis, United Kingdom). Both of these vaccines contain the combination protein AG85-ESAT6.

Researchers from the Institute of Infectious Biology. Max Planck (Berlin, Germany) has created a new recombinant vaccine using genetic engineering technologies. They developed a genetic engineering strain of BCG, capable of producing the protein Listeriolysine (Hly) secreted by Listeria. Listerolysin makes holes in the phagosomal membrane and enters the phagosome, where M. tuberculosis is found. In addition, the urease C gene has been removed from BCG, which normally neutralizes the acidity of the phagosome, creating ideal environmental conditions for listeriolysin. This system elicits a strong immune response and should theoretically stimulate the development of long-term immunity.