Résumé
Tuberculosis is a major yet preventable global health problem, with an estimated 10 million new cases worldwide in 2018 that resulted in more than 1.5 million deaths, making it the leading infectious disease cause of death worldwide. One quarter of the global population is estimated to be infected with Mycobacterium tuberculosis. TB infection is classically defined as a "state of persistent immune response to stimulation by M. tuberculosis antigens with no evidence of clinically manifested TB disease". The vast majority of infected people have no signs or symptoms and are not infectious, although they are at risk of progression from infection to disease and becoming infectious. As TB infection is more likely to progress rapidly to TB disease in children and adolescents, household contacts of infectious TB patients in these age groups are at particular risk. The United Nations high-level meeting on TB, in September 2018, further emphasized the importance of strengthening implementation of TB preventive treatment (TPT), with the goal of 30 million people, including 4 million children < 5 years of age, receiving TPT by 2022. Although TPT has been available for more than 60 years and in spite of strong evidence of its effectiveness, its uptake and scale-up have been slow, mainly because of the limitations of both available diagnostic assays and regimens (long duration, cost, toxicity, adherence issues and operational aspects).The availability of and access to new drugs or regimens that can be administered for a shorter time and with fewer adverse events than the current 6-12-month TB preventive strategies is essential to ensure wider-scale implementation. Even with improved TPT options in the future, treatment of infection will remain essential for effective TB control. Scaling-up of TPT would have to be accompanied by active case finding, better treatment for TB disease and other measures to reduce transmission and unfavourable outcomes of disease episodes. Parallel improvements in these areas and the development of new TB vaccines will be critical.