PROJECT SUMMARY/ABSTRACT Three million global tuberculosis (TB) cases remain undiagnosed each year, which is a key factor underpinning why TB is the leading cause of death among people living with HIV (PWH) and the leading infectious cause of death worldwide. While community-wide screening for TB in high-burden settings is recommended by WHO and may reduce community prevalence, it is unlikely to be a scalable TB control strategy. Leveraging trained peers (recent TB patients) to undertake community-based, systematic TB screening among non-household contacts of newly diagnosed TB patients, including casual contacts at community venues, may be an efficient and sustainable strategy to facilitate early TB diagnosis and linkage to care; however, little is known about whether such a strategy is feasible and acceptable to undertake in low-resource, high TB burden settings. Through targeted training and strong mentorship in implementation science methods, I will develop and evaluate a theory-informed, multicomponent, peer-led strategy to undertake community-based, systematic TB screening among non-household contacts of newly diagnosed TB patients attending two public health facilities in Lusaka, Zambia. This proposal builds upon the research collaboration I began developing during my infectious disease fellowship and leverages the robust experience and infrastructure of the Centre for Infectious Diseases Research in Zambia (CIDRZ). In Aim 1, I will undertake mixed-methods research among key stakeholders to identify barriers to undertaking TB screening among non-household contacts using peers. In Aim 2, I will use a discrete choice experiment among TB patients, at-risk community members, and community venue owners, to determine their preferences for the mode of delivery for the implementation strategy components. Findings from Aims 1 and 2 will inform the design of a multicomponent, peer-led TB contact tracing strategy among non-household contacts that will be evaluated in Aim 3, during a 6-month pilot to assess its feasibility, acceptability and reach. My overall training objective is to develop implementation science expertise; I will accomplish this by undertaking carefully selected coursework, workshops, and seminars, and through the guidance of highly accomplished mentors who are experts in international Implementation science research, mixed-methods research and multicomponent TB/HIV implementation strategies. My training objectives sequentially map onto my research aims and are to: (1) gain experience in the application of mixed-methods for implementation science research; (2) develop expertise in using implementation science methods to develop multicomponent implementation strategies; (3) develop a strong foundation in study designs and analysis approaches for interventional implementation research. My career goal is to be an independent physician-scientist who applies implementation science methods to improve TB and HIV outcomes in low-resource se...