Epidemiology, diagnosis and treatment of asymptomatic tuberculosis: an expert review.

BACKGROUND: There is increasing evidence to suggest that a significant proportion of prevalent TB is asymptomatic (aTB). In recognition of the potential implications for disease elimination, the World Health Organization (WHO) formally included aTB within its case-definitions in 2024. METHODS: A literature review was conducted to guide discussions during the consultation for the revised definitions through a purposive synthesis of selected literature and input from experts to identify ongoing unpublished research. Three broad domains of relevance to asymptomatic TB were selected: 1) epidemiology; 2) diagnostics and 3) treatment. RESULTS: The estimated proportion of prevalent TB that is asymptomatic varies from 27 - 82% depending on symptom thresholds. Emerging evidence suggests that aTB can be transmissible. Asymptomatic TB may be identified during community screening through digital chest X-rays and molecular testing, however, more sensitive diagnostics assays and alternative sampling approaches to sputum require development. Ongoing trials are investigating novel shorter course regimens for aTB. CONCLUSION: Many critical knowledge gaps remain in our understanding of aTB. The revised definitions by WHO are expected to catalyze research in this area and support a coordinated effort to accelerate global disease elimination.