Estimating the Burden of Subclinical TB from a Postmortem Cohort

Background: Subclinical tuberculosis (scTB) is asymptomatic and challenging to diagnose, with its true prevalence in high-burden settings remaining poorly defined despite potential implications for transmission. Methods: Between January 2021 and June 2022, 63 postmortem examinations were conducted on individuals without clinical evidence of TB at Mulago National Referral Hospital, Uganda. Lung tissue, bronchoalveolar lavage, spleen, and lymph nodes were analysed using MGIT culture, Ziehl-Neelsen staining, and MPT64 antigen assays to detect Mycobacterium tuberculosis. Results: scTB was identified in 4 of 63 cases (6.3%; 95% CI: 1.76–15.47%). Three individuals had positive cultures without visible lesions; one exhibited classical TB lesions at postmortem. Conclusions: Our findings suggest that scTB is more prevalent in the general population than previously estimated through community surveys and household contact tracing studies. This highlights the hidden burden of scTB and emphasizes the need for improved diagnostic tools to detect this asymptomatic stage, crucial for TB control.