• Tuberculosis (TB) is a major health threat caused by the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb).
  • Globally, 10 million individuals fell ill of TB and 1.4 million died in 2019.
  • The COVID-19 pandemic has severely impacted on TB notifications in 2020, thereby, markedly increasing morbidity and mortality caused by TB.
  • The lung is the most frequent site of disease manifestation, the site of pathogen entry and the source of dissemination.
  • In the infected lung, granulomas are formed at the site of Mtb persistence which primarily consist of macrophages of different maturation stages and T lymphocytes.
  • Solid granulomas contain Mtb, thus preventing outbreak of active disease. The individual is now latently infected.
  • Once Mtb evades immune control, granulomas become necrotic and later caseous. Active TB disease has started.
  • Diagnosis of TB is done by chest X-ray, microscopy, bacterial culture, molecular test, and immunologic test.
  • TB can be cured by a combination of 3-4 specific drugs given over a period of 6-9 months.
  • Increasing incidences of multi-drug and extensively drug-resistant Mtb render therapy difficult to impossible.
  • The current vaccine, Bacille Calmette-Guérin (BCG) prevents extrapulmonary childhood TB but fails to protect against pulmonary TB in all age groups.
  • New vaccines against TB are urgently needed. New candidates that have entered clinical trials are killed whole cell vaccines, recombinant live vaccines, Mtb antigen-adjuvant formulations or viral vectors expressing Mtb antigens.