Latent tuberculosis: LHSI experts took part in the session of the global conference on tuberculosis UNION-2021

Latent tuberculosis infection (LTBI) is defined as a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens with no evidence of clinically manifest active TB.

LHSI has been active in the detection of active TB for over 10 years. The organization participated in two TB REACH projects – W2 and W6.

In 2018, the World Health Organization (WHO) issued Updated Consolidated Guidelines on programmatic management of latent TB infection (LTBI) where it notes that there is no gold standard test for LTBI. The vast majority of infected people have no signs or symptoms of TB, but they are at risk of developing active TB. Among risk groups, where the probability of progression to active TB disease may be higher, are the following: 

1. Adults, adolescents, children and infants living with HIV
2. HIV-negative household contacts
3. Other HIV-negative at-risk groups

Either a tuberculin skin test (TST) or interferon-gamma release assay (IGRA) can be used to test for LTBI.

In Ukraine, tuberculin test is predominantly used to identify latent forms of TB, but QuantiFERON technology has already appeared, and there are some challenges in using two types of tests in health care. In 2018, LHSI is implementing a project aimed at active detection of TB cases among people in difficult life circumstances at risk of tuberculosis. The project is supported by the Public Health Alliance under a grant from the Global Fund to Fight AIDS, Tuberculosis and Malaria. Among project activities - social support of children from families in difficult life circumstances to detect LTI and psychological support to such families where the child undergoes a course of preventive treatment for LTBI. Among LHSI clients are families where LTBI was detected by doing tuberculin skin test, but when parents repeated test suing IGRA it was negative.

Earlier, the WHO LTI Guidelines (2018) noted insufficient evidence research on IGRA tests.

It was therefore very interesting for LHSI experts to attend a special session SS-02 'Bridging the gap in TB infection screening: new solution for easier access to IGRA testing' that was dedicated to rapid IGRA tests. The session was part of the 52nd Union World Conference on Lung Health, which is being held online this year. The most interesting was a Q&A part of the session, and LHSI had the opportunity to put questions to the prominent TB testing expert. From the discussion, it became obvious that there is yet no single recommended algorithm for what to do when such cases happen, but the general recommendation sounded like that there is no consensus on whether to treat such patients, especially children, except for cases of immune-suppression. Seminar leaves many questions unanswered, but one thing is clear - more research is needed on testing algorithms for LTBI.

Coming back to WHO Guidelines for the programmatic management of LTBI, for Ukraine it is necessary:

14. As part of the national TB program, prepare a national plan for the programmatic management of LTBI, including prioritization of identified high-risk groups based on the local TB epidemiological situation and health system characteristics;
14. Create an enabling environment for policy and program implementation, including development of national and local interventions and standard operating procedures to support the WHO recommendations implementation.