Avances en tuberculosis en el 54° Congreso Chileno de Enfermedades Respiratorias. 2a parte: Nuevas normas técnicas chilenas para el control y eliminación de la tuberculosis

Abstract

The incidence of tuberculosis (TB) in Chile has been increasing in the last five years except at the beginning of the Covid-19 pandemic where TB screening has clearly decreased. The current epidemiological scenario is far from the goal proposed in the National Health Strategy (NHS) of the decade 2011-2020 (a national government plan for relevant diseases in the population) which was to achieve an incidence rate of all forms of TB less than 5/100,000 inhabitants. The new NHS for the decade 2021-2030 proposes to reduce the incidence of the disease through timely and early diagnosis by focusing interventions on populations at risk of the disease (vulnerable groups), as an active screening and not only as screening for spontaneous consultations of respiratory sympto­matic or mass screenings that may not select the population at risk. It also proposed to intervene in prevention prioritizing the study and treatment of the population with Latent Tuberculosis Infection (LTI) at higher risk of progression to the disease. Finally, it intends to improve the efficiency of the TB treatment process, optimizing access and adherence to therapies of active TB cases as a meas­ure to increase the cure rate. A new ministerial standard for the management and control of TB can greatly help this proposal. This standard, fully effective in 2022, provides the operational tools to meet the objective set for the new NHS. The standard incorporates activities aimed at achieving greater coverage of study and treatment of LTI in specific groups, which include, in addition to child contacts, adult contacts and other vulnerable groups. Therapy for this condition will be performed using the combination of isoniazid with rifapentine preferably. Therapy is administered under super­vision and patients receive therapy once a week for 12 doses for 3 months. This therapy has shown better adherence and lower liver toxicity. For the timely diagnosis of TB, case finding has focused on respiratory symptoms (cough and expectoration) for more than 2 weeks, in individuals that be­long to one of the vulnerable groups, or that have additional clinical features very suggestive of the disease (fever, afternoon sweats, hemoptysis, compromise of the general condition). Smear sputum as a diagnostic tool is no longer used due to low sensitivity and it was replaced by molecular tests in automated platform for DNA amplification of the mycobacterium TB complex. The more used and available in public health services is GeneXpert MTB / RIF Ultra, which also provides information on susceptibility to rifampicin through the identification of a specific genome mutation (rpoB gene). With this technology, the diagnostic process is streamlined (you can obtain results during the day of execution, usually it would not take more than 2 hours) and sensitivity is high (sensitivity very similar to culture). Treatment of TB sensitive to first line drugs (rifampicin, isoniazid, ethambutol and pyrazi­namide) consists of daily administration in the initial phase (with four drugs) for 2 months and in the continuation phase (with isoniazid and rifampicin) for 4 months, fully supervised. In rifampicin resis­tant TB, the treatment is a shortened oral regimen of 9 months with new drugs: bedaquiline, linezolid, clofazimine and levofloxacin (six months with four drugs, followed by three months with clofazimine and levofloxacin). These high-quality therapies are safe and promise better healing results. The new national standards mean a greater coverage for the eradication of the reservoirs of the disease and a greater precision in the diagnosis of the sources of community transmission of tuberculosis, being a significant contribution towards the path of control and elimination of TB in the country.