Enlaces transversales de Book para 1. Background
Tuberculosis infection (TBI) is defined as a state of persistent immune response to stimulation by M. tuberculosis antigens with no evidence of clinically manifest TB disease (1). As there is no “gold standard” test for TBI, the global burden is not known with certainty; however, about one fourth of the world’s population is estimated to have been infected with M. tuberculosis (2,3). The vast majority of people with TBI have no signs or symptoms of TB disease and are not infectious, although they are at risk of developing TB disease and becoming infectious. Several studies have shown that, in recent decades, an average 5–10% of people who are infected will develop TB disease over the course of their lives, usually within the first 5 years after initial infection (4,5). The risk for TB disease after infection depends on several factors, the most important being immunological status (1). At the second United Nations high-level meeting on TB in 2023, Member States committed themselves to providing TPT to at least 45 million people between 2024 and 2027 (6).
TPT is a critical component of the WHO End TB Strategy and of other work to eliminate TB (7–9). The efficacy of currently available TPT regimens ranges from 60% to 90% (1). The potential benefit of treatment should, however, be carefully balanced against the risk of drug-related adverse events. Mass, population-wide testing and treatment of TBI are not feasible at present because the tests are imperfect, there is a risk of serious, potentially fatal adverse drug reactions, and the cost would be high, thus providing unclear benefit for populations at lower risk. The benefits of TPT are more likely to outweigh harm in infected individuals in population groups in whom the risk for progression to TB disease substantially exceeds that of the general population. In people exposed to MDR/RR-TB, which is more difficult to treat than drug-susceptible TB, provision of suitable TPT may be more justifiable. Programmatic management of TPT (PMTPT) involves a comprehensive package of interventions: identifying and testing those individuals who should be tested, delivering effective, safe treatment in such a way that the majority of those who start a treatment regimen will complete it with no or minimal risk of adverse events, and monitoring and evaluation. PMTPT fits within a larger framework of preventive actions envisaged in pillars 1 and 2 of the End TB Strategy, from screening for TB disease, infection control, prevention and care of HIV and other co-morbidities and health risks, access to universal health care, social protection and poverty alleviation.