Reported Tuberculosis Symptoms: An Inadequate Classifier of Disease State

Around half of people identified with tuberculosis (TB) during prevalence surveys do not report symptoms, prompting increased interest in the public health implications of asymptomatic TB (aTB), as distinct from symptomatic TB (sTB). A recent World Health Organization report proposes investigating the optimal treatment for aTB, stratifying notification data by symptom status, and publishing incidence estimates based on sTB. We have concerns that the proposed use of aTB/sTB case definitions for surveillance, burden estimation, and clinical management is not supported by evidence. Although TB symptoms are linked to disease severity, we show that self-reported symptoms are an inadequate classifier of disease state, heavily influenced by context and substantial interviewer variability, and TB symptoms may frequently have alternative causes. We advocate for the adoption of more robust measures of severity, better reflecting underlying pathophysiology. Research on the TB disease spectrum should prioritize more objective severity metrics, alongside or instead of symptom-based classification.