Implications of study findings
TB
DISEASE
Our findings indicate that systematic screening for TB that is based on symptom screening alone is not sufficient to achieve a large reduction in TB prevalence over a period of several years. Including chest X-ray screening alongside TB symptom screening could substantially increase the sensitivity of systematic screening for TB and is increasingly feasible with the advent of mobile X-ray machines (including ones that can be transported in a backpack) and computer-assisted diagnosis of digital X-ray images. In settings with high general population TB prevalence (such as the communities in our study), systematic screening for TB based on both symptoms and chest X-ray might be able to achieve a considerable reduction in TB prevalence and transmission, in absolute as well as relative terms; such a strategy could be evaluated in future research. The accuracy, in particular the specificity, of computer-aided diagnosis has been improved since the TREATS TB prevalence survey was conducted [The 2021 WHO TB screening guidelines included a statement that “Systematic screening for TB disease may be conducted among the general population in areas with an estimated TB prevalence of 0.5% or higher,” but the evidence for this is weak. They also stated that a range of approaches to such screening could be considered, including diagnostic testing (using molecular tests) for everyone or for those who screen positive on TB symptoms or chest X-ray. Our study provides rigorous evidence about the impact of systematic TB symptom screening on TB prevalence in communities with an average prevalence of >0.5%, which can be taken into account in future updates to these guidelines.Our study does not provide clear evidence about the effect of UTT for HIV on TB prevalence, because ART coverage was high in all trial arms by the time of the TREATS TB prevalence survey. However, TB prevalence remained approximately 2 times higher among HIV–positive than HIV–negative individuals, after adjusting for sex and age group and study triplet, compared to around 3 to 4 times higher in similar study communities in the ZAMSTAR trial TB prevalence survey that was conducted in 2010 when ART coverage was much lower [