Consolidated Guidelines

The data used to inform this recommendation came from a systematic review of the diagnostic accuracy of using symptoms and chest radiography to detect TB disease among individuals aged 15 years and older with negative or unknown HIV status. The review included studies of screening conducted in the general population (including several prevalence surveys conducted in African and Asian countries), as well as screening conducted in high-risk groups (including contacts of TB patients, prisoners and others).

Fig.1 summarizes the potential contribution of TB screening to standard TB care practices based on the above frameworks for TB screening and shows the conceptual framework that guided the 2021 update to the TB screening guidelines.

Fig. 1. Conceptual framework for the 2021 WHO update to guidelines for systematic screening for TB. Numbers in parentheses refer to the PICO (population, intervention, comparator and outcome) questions that guided the evidence gathering

1. Global tuberculosis report 2018 (WHO/CDS/TB/2018.20). Geneva: World Health Organization; 2018 (http://apps.who.int/iris/bitstream/handle/10665/274453/9789241565646-eng.pdf?ua=1, accessed 18 December 2018).
2. The End TB Strategy: global strategy and targets for tuberculosis prevention, care and control after 2015.

During the guideline development process, the Guideline Development Group identified important knowledge gaps that need to be closed through both primary and secondary research in order to better inform the adoption of current IPC practices and, potentially, of new practices.

The general research gaps listed below are to be prioritized for all IPC interventions:

The threats posed by epidemics, pandemics and AMR have become increasingly evident as ongoing universal challenges, and they are now recognized as a top priority for action on the global health agenda. Effective IPC is the cornerstone of such action. The International health regulations position effective IPC as a key strategy for dealing with public health threats of international concern (70).

Respiratory protection controls are designed to further reduce the risk of exposure to M. tuberculosis (and other airborne pathogens) for health workers in special areas and circumstances. The recommendations given here are aimed at strengthening these controls, and preventing the inadequate implementation of respiratory protection programmes that may lead to a false sense of security and therefore increase the risk to health care staff.

To reduce the risk of transmission of M. tuberculosis, air can be made less infectious through the use of three principles: dilution, filtration and disinfection. Environmental controls are aimed at reducing the concentration of infectious droplet nuclei in the air. This is achieved by using special ventilation systems to maximize airflow rates or filtration, or by using germicidal ultraviolet (GUV) systems to disinfect the air.

A set of administrative controls is the first and most important component of any IPC strategy. These key measures comprise specific interventions aimed at reducing exposure and therefore reducing transmission of M. tuberculosis. They include triage and patient separation systems (i.e. management of patient flows to promptly identify and separate presumptive TB cases), prompt initiation of effective treatment and respiratory hygiene.

Evidence summary and rationale

The recommendations given below on TB-specific interventions are not envisioned as stand-alone measures; rather, they are components of a comprehensive hierarchy of controls, which in turn is a component of the overall framework of IPC practices, and depends on the adoption of a multimodal strategy. Thus, the adoption of several elements needs to be integrated.