Mass TB screening in a Brazilian prison: prevalence and implications for control

BACKGROUND TB remains a major public health challenge in prisons due to overcrowding and limited health care access. Evidence on integrated mass screening strategies using molecular testing and computer-aided detection (CAD) in Brazilian prisons is scarce. METHODS A cross-sectional mass screening study was conducted in a male prison in southern Brazil. Screening included symptom assessment, digital chest X-ray with automated interpretation (LunitTB), and GeneXpert MTB/RIF testing. TB infection (TBI) was assessed using interferon-gamma release assay (IGRA). Socio-demographic, clinical, and behavioural data were analysed to identify factors associated with TB. RESULTS A total of 652 (96.3%) of 677 individuals completed screening; 120 (18.4%) underwent IGRA testing. Active TB prevalence was 4.7% (31 cases). TB was associated with contact with a TB case within the same cell, alcohol use disorder, weight loss, chest pain, and night sweats. Among 117 individuals tested, 62% were TBI-positive. The CAD system showed strong performance (area under the curve: 0.90; optimal threshold: 43.5). CONCLUSION Systematic screening revealed a high burden of TB and TBI in this setting. Chest X-ray combined with CAD was effective, identifying cases likely missed by symptom-based screening alone. .