Since 2011, WHO has recommended that people living with HIV be systematically screened for TB disease at each visit to a health facility. The recommendation is based on the high risk of this group for TB and mortality and a lingering gap in case detection in this population. In 2019, people with HIV were at 18 times greater risk for incident TB than people without HIV and close to one third of deaths from AIDS were due to TB (2). Only 56% of the total estimated number of HIV-positive incident TB cases were detected in 2019 (2). Early detection and timely treatment of TB among people living with HIV is critical for reducing mortality.
To date, the recommendation has been to screen for four primary symptoms of TB among people living with HIV: cough, fever, weight loss or night sweats. Screening with the WHO four-symptom screen (W4SS) is recommended for all people living with HIV at every encounter with a health-care worker, both to detect prevalent TB disease and to rule it out before initiation of TPT. Recent evidence indicates, however, that the accuracy of W4SS may be suboptimal for all subpopulations living with HIV (35). Therefore, for the 2021 update to the TB screening guidelines, a systematic review and a meta-analysis of individual patient data were commissioned to evaluate the performance of W4SS and alternative screening tools among subpopulations of people living with HIV, each with distinct clinical characteristics and implications for implementation:
- Outpatient people living with HIV not receiving ART: This population may include people with newly diagnosed HIV, those who discontinued ART and are re-engaging in care and those who experience ART failure. This subpopulation is at a high risk of TB disease or reactivation because of their probably weakened immune system. They are also at greater risk of death, and therefore a highly sensitive and specific screening strategy is required to ensure rapid initiation of treatment for TB disease or infection, as appropriate. Ideally, TB screening in this population will be accompanied by prompt enrolment in HIV/AIDS care and initiation of ART. Staging of HIV disease and testing to exclude TB with LF-LAM or mWRD is recommended in people with advanced HIV disease (i.e. ≤ 200 CD4 cells/µL or in clinical stage 3 or 4) (12).
- Outpatient people living with HIV on regular ART: Once in regular ART care, this population is likely to have suppressed viral replication of HIV and therefore a reduced viral load and significant immune recovery. This decreases the chances of TB reactivation and incident disease. Thus, this population is at lower risk of TB and has a physiological presentation similar to that of non-HIV-infected screening participants. People living with HIV who are currently in care should be screened for TB at every regular contact with the health services as part of integrated HIV care.
- Medical inpatients living with HIV: This population is usually at an acute state of illness and requires immediate care, including screening, diagnostic evaluation and treatment, to decrease the risk of death. Regardless of their ART status, people living with HIV should be screened for TB at any episode of hospitalization.
- Pregnant women living with HIV: This is a key population, given the suppressed immune status of the mother and the importance of protecting the health of the fetus. TB screening for this population should be integrated with prevention of mother-to-child transmission and antenatal care.
- Children < 10 years living with HIV: This subpopulation is addressed in 6.3.
Health-care workers should suspect TB in any person living with HIV. People with HIV who screen negative for TB and show no evidence of TB disease should be offered TPT if they are eligible.