OA-208 Evaluating the impact of computer-assisted x-ray diagnosis and other triage tools to optimise Xpert orientated community-based active case finding for TB and COVID-19 (XACT-19)

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Background Almost 40% of persons newly diagnosed with TB are unreported. Detecting cases in TB/HIV endemic communities have been restricted by a lack of sensitive and user-friendly point-of-care (POC) diagnostic tools. Computer-aided detection (CAD) has been recommended by the WHO for screening for TB, however, implementation of CAD in community-based active case finding (ACF) is unclear. We aimed determine the adjunctive role of CAD in Xpert-orientated community-based ACF for TB. Methods In this ongoing, EDCTP-funded (RIA2020S-3295), open-labelled randomised controlled trial (RCT), high-risk persons (symptomatic and/or HIV-infected) with presumed TB were recruited from TB/HIV endemic communities in South Africa and Zambia (Zimbabwe is an additional site). Using a low-cost mobile van staffed by three healthcare workers and equipped with an ultra-portable x-ray and GeneXpert® system, participants were randomized into either ‘CAD + POC Xpert’ (Arm 1: CAD followed by Xpert MTB/RIF Ultra in CAD-positive participants using a CAD4TB v7 threshold of 10 [South Africa] and 50 [Zambia] based on prior population-specific calibration), or ‘POC Xpert alone’ (Arm 2: POC Xpert MTB/RIF Ultra only). The primary outcome was time to detection of microbiologically proven TB (Xpert and/or culture positivity). Here we present an interim trial progress report. Results From Feb 2022, a total of 505 participants have been enrolled (256 [50.7%] from South Africa and 249 [49.3%] from Zambia). 26.9% (136/505) of participants were HIV-infected (median CD4 of 609). 33/505 (6.5%) tested positive for TB (25/256 [9.8%] in South Africa and 8/249 [3.2%] in Zambia). 15 participants underwent screening to detect 1 case of TB. Of TB-positive participants, 7/33 (21.2%) were smear positive. Conclusion Community-based ACF detected a high burden of TB, of which a significant minority (~20%) was probably infectious. These data have implications for ACF strategies in high burden settings.

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