PROJECT SUMMARY Tuberculosis (TB) remains a global health emergency, responsible for 10 million new cases and 1.5 million deaths in 2018. The Stop TB Partnership has set very ambitious targets that include a 50% reduction in TB incidence from 2015 to 2025. Strategies to find people with active TB earlier in their disease course must therefore be rapidly scaled up if TB control targets for 2025 are to be approached. However, active case finding or TB is expensive and difficult to implement in practice, particularly tracing close contacts of newly diagnosed TB cases. One innovative approach to contact tracing is to forego household visits in favor of small incentives to the TB case and their contact for the contacts to present to the clinic for TB screening. This proposed research is a novel study looking at barriers to implementation of incentive-based contact tracing, refining the strategy to modify these barriers and pilot testing it in the high burden setting of rural South Africa. We will measure acceptability, feasibility, reach, implementation and generate pilot effectiveness data which can be used to plan for scale-up. The proposed study will be in the rural district of Vhembe, South Africa – a district with a TB incidence of 350 per 100,000/year. We will assess barriers to implementation using quantitative surveys and qualitative interviews with TB cases and their contacts who received the intervention in the context of a cluster-randomized controlled trial, as well as healthcare workers. We will prioritize barriers with stakeholders and devise a refined incentive-based tracing implementation strategy. We will pilot test this strategy in 6 public primary health clinics within Vhembe, and examine implementation and preliminary effectiveness. The specific aims of this research are: (1) To identify individual and systems-level barriers and facilitators to the implementation of incentive-based contact tracing in a high burden setting; (2) To develop and pilot test an improved contact tracing strategy. This multidisciplinary research represents an innovative path toward achieving medium-term TB control targets in a key epidemiological setting, and can also serve as a methodological example of how to improve real-world decision-making across a broad array of other fields in the context of urgent and ambitious population health priorities.