Study population
TB, pulmonary TB disease
The study will attempt to enroll all close child contacts of individuals diagnosed and treated for infectious drug-sensitive TB in the study clinics. Good Clinical Practice (GCP)-trained study and clinic staff will enroll participants. Eligibility criteria for index patients and child contacts are pragmatically designed to align with the Ethiopian and South African National Guidelines regarding TPT eligibility. We will enroll index participants with pulmonary TB disease who (1) are 18 years and older, (2) attend a study clinic for TB care and live in the catchment area of that clinic, (3) are willing to have a home visit and disclose their TB diagnosis to household members, and (4) who provide informed consent. In South Africa, all index patients will need bacteriologic confirmation of pulmonary TB disease by smear, Xpert, and/or liquid mycobacterial culture. In Ethiopia, index patients may have bacteriologic confirmation or clinical diagnosis. Index patients in both countries will be excluded if there is evidence of rifampin and/or isoniazid resistance on Xpert or drug sensitivity testing from isolates identified on culture (late exclusion) or if the household has more than one index patient and whose child contacts have already participated in the study. Child contacts will be enrolled if (1) they are less than 15 years of age in Ethiopia or less than 5 years of age in South Africa, (2) they are a close contact of the index patient, and (3) their parent or legal guardian is willing to provide informed consent. Additionally, in Ethiopia, children 12 years and older must be willing to provide assent. Child contacts in both countries will be excluded if any index patient in their household has drug-resistant TB by either Xpert or drug sensitivity testing. Eligibility criteria will be adapted as country guidelines are updated.