Screening

Systematic screening in the general population is conducted on the premise that it bears dual benefit: to the persons diagnosed with TB and to the community in which screening is conducted. Individuals found to have TB may benefit from less diagnostic delay, improved treatment outcomes, and lower costs and financial losses associated with the disease. It also benefits public health by reducing the population prevalence of TB, thereby reducing further transmission of TB.

Case detection is a crucial step in the cascade of care for children with TB; however, for most children who die from TB, the disease is never diagnosed (80). Children and adolescents who are younger than 15 years represented approximately 12% of incident cases but 16% of the estimated 1.4 million deaths from TB in 2019 (1). This relatively higher share of mortality in children highlights the urgent need for improved case detection and subsequent access to preventive and curative treatment in this age group, particularly for those at highest risk.

TB remains the primary cause of AIDS-related morbidity and mortality worldwide, despite impressive scale up of antiretroviral treatment (ART). In 2019, TB was associated with an estimated 208 000 (30%) AIDS-related deaths (1). Global estimates show a 44% gap in case detection among people with HIVassociated TB (1). A systematic review of postmortem studies of global AIDS-related deaths in adults found TB to be the primary cause of death in 37.2% of cases (95% CI: 25.7–48.7). TB was undiagnosed prior to death in 45.8% of cases (95% CI: 32.6–59.1) (75).

This recommendation concerns interventions that should be undertaken in addition to passive casefinding practices, namely properly triaging and evaluating people seeking care who report signs or symptoms of TB, which should be done in all settings and is particularly important to implement rigorously among people who have risk factors for TB.

The GDG considered that all three approaches – symptom screening, CXR and mWRD – may have roles in screening for TB disease in the general population. The ranking of the tools according to accuracy proposed by the GDG is: first, CXR; second, mWRDs; third, screening for any TB symptom (higher sensitivity and lower specificity); and fourth, screening for any cough or cough lasting 2 weeks or longer (lower sensitivity and higher specificity).

A prisoner is anyone held in a criminal justice facility or correctional facility during the investigation of a crime, anyone awaiting trial and anyone who has been sentenced. In addition, people residing in a correctional facility are almost always in close contact with several other inmates; thus, whenever a person residing in a prison is diagnosed with TB, prisoners who have been in close contact with that person should be investigated (see Recommendation 4).

Countries should position the W4SS, CRP, CXR and mWRD in combination with diagnostic evaluation using mWRDs and LF-LAM (8) within national TB screening and diagnostic algorithms according to their feasibility, the level of the health facility, resources and equity. Algorithms exploring the available screening tools are presented in the operational handbook, including modelled performance of accuracy and yield (7).

TB is the main cause of hospitalization and mortality among people living with HIV. The assessment of the performance of an mWRD used as a combined TB screening and diagnostic strategy for medical ward patients with HIV included 4 studies in Ghana, Myanmar and South Africa with a total of 639 participants (see Web Annex B, Table 15, and Web Annex C, Table 8).