Tuberculosis contact investigation in low prevalence countries: a European consensus

Abstract

Contact investigation to identify individuals with tuberculosis and latent infection with Mycobacterium tuberculosis is an important component of tuberculosis control in low tuberculosis incidence countries. This document provides evidence-based and best-practice policy recommendations for contact tracing among high-and medium-priority contacts in a variety of settings. It provides a basis for national guidelines on contact investigation and tuberculosis outbreak management, and should support countries and tuberculosis control managers in evaluating and revising national policies. A review of existing guidelines, a literature search, several meetings and consultation with experts were used to formulate and grade recommendations for action during contact investigation.Available tests to identify individuals with latent infection with M. tuberculosis are designed to identify immune response against mycobacterial antigens and have variable predictive value for the likelihood to develop active tuberculosis in different populations. Contact investigation should therefore be limited to situations with a clear likelihood of transmission or to those with a higher probability of developing active tuberculosis, for instance, young children and immunocompromised persons. A risk assessment-based approach is recommended, where the need to screen contacts is prioritised on the basis of the infectiousness of the index case, intensity of exposure and susceptibility of contacts.

Interferon- release assays for the diagnosis of latent Mycobacterium tuberculosis infection: a systematic review and meta-analysis

“…As part of reaching this goal, individuals infected with M. tuberculosis need to be identified and offered preventive therapy to stop the progression to active tuberculosis and prevent further M. tuberculosis transmission [3]. Thus, there is a need to develop more accurate methods for the detection of LTBI, and to provide evidencebased guidance on the use of such methods before they can be adopted by national tuberculosis screening programmes [4,5].…”

Yield of tuberculosis contact investigation in a low-incidence country

“…Where adequate resources exist and when active TB cases are being successfully treated, efforts should be directed towards contact tracing strategies to allow the early identification of TB contacts, i.e., individuals exposed to someone who has been diagnosed with TB, and to offer appropriate treatment for both latent TB (LTB) infection and active TB (5,6). TB contact tracing, and partner notification have been revealed as a valid tool to stem the tide of TB infection, in particular among disadvantaged groups (3,7).…”

“…Under conditions particularly favorable for transmission, an individual with undiagnosed active TB may potentially cause a TB outbreak in confined settings such as schools, prisons and other congregate settings (7,10).…”

Immunological Signatures Identifying Different Stages of Latent Mycobacterium tuberculosis Infection and Discriminating Latent from Active Tuberculosis in Humans

“…Most latently TB infected (LTBI) subjects control the infection thanks to appropriate immune responses, and they do not develop any sign of disease. Nevertheless, these LTBI subjects have a lifetime risk of about 10% to reactivate their infection, leading to progression to TB disease, this risk being higher in different clinical conditions associated with immune deficiency [2,3]. Despite being asymptomatic, these subjects constitute an enormous reservoir of M. tuberculosis and TB elimination requires focus on sterilizing the pool of LTBI individuals [4,5].…”