Tuberculosis : Bacillus Calmette-Guérin (BCG) Vaccine

The Bacillus Calmette-Guérin (BCG) vaccine is a cornerstone in the prevention of tuberculosis (TB) and certain other mycobacterial infections. Developed by Calmette and Guérin, this live attenuated vaccine derived from Mycobacterium bovis was first administered to humans in 1921. As the sole vaccine against TB, BCG holds a significant place in global public health, especially in tuberculosis-endemic regions.

BCG's effectiveness lies in its ability to induce an immune response against mycobacterial pathogens. Over the years, various strains of the BCG vaccine have been developed, each with distinct characteristics and efficacies. These variations arise from differences in the production processes and genetic compositions of the strains. The selection of strains used in different countries is influenced by these factors, along with supply logistics managed by organizations such as UNICEF and the Global Alliance for Vaccines and Immunization.

While the efficacy of BCG vaccines in preventing TB varies across different studies and populations, overall, it has shown a significant impact in reducing the risk of tuberculosis. Historical studies, such as the one conducted by Townsend et al among American Indians and Alaska Natives, highlight its long-term effectiveness in reducing TB incidence and mortality. Despite its variability in efficacy and the complexity of...