Asymptomatic tuberculosis (TB) poses a major challenge to global TB control. Quantifying its contribution to transmission remains a critical question. Although modelling studies have attempted to address this issue, empirical evidence from real-world settings is scarce. In this study, we estimated the contribution of asymptomatic TB to transmission in China using genomic epidemiology data from five population-based studies, encompassing 6,387 TB patients and 1,626 genomic-clustered patients. Transmission were classified as originating from either asymptomatic or symptomatic TB by comparing reported symptom onset dates with phybreak-inferred transmission timings. Across the study regions, 25.0%-51.3% of transmission was attributed to asymptomatic TB, indicating its substantial role in sustaining transmission. However, accurate estimation is hindered by the subjectivity of symptom reporting and reliance on passive case-finding. While this study likely underestimates the true contribution, it establishes a genomic epidemiology-based framework for future refinement. From a public health perspective, the priority should not be precise quantification but rather a shift toward active case-finding to detect both asymptomatic patients and symptomatic patients who have not sought care, thereby disrupting hidden transmission chains and advancing the End TB goals.
Li et al. (Tue,) studied this question.