Composite The Duke University Medical Center (DUMC) Clinical Trials Unit (CTU) proposes to address the key scientific areas of translational research and optimization of clinical management in children and adults, and prevention of mother to child transmission.The CTU and its affiliated Clinical Research Sites (CRS's) bring scientific leadership, a rich history of successful collaborative clinical research within networks, a strong and efficient organizational foundation for the conduct of rigorous clinical research, and access to growing numbers of underserved persons living with HIV/AIDS (PLWHA) in the US Southeast and Tanzania. The scientific leadership of the CTU and CRS investigators is reflected in their past participation in the Adult and Pediatric AIDS Clinical Trials Groups (ACTG's), and the expanding portfolio of NIH-funded research at DUMC and the Kilimanjaro Christian Medical Centre (KCMC). The three CRS's included in the CTU proposal each bring unique value and are highly motivated to perform the proposed work, and together they will constitute a formidable research enterprise. Their interactions will be guided by an administrative structure which supports a dynamic intellectual environment to enhance scientific creativity, clear roles and responsibilities for investigators and staff, facile and regular communications, harmonized standard operating procedures across CRS's which emphasize CTU accountability through quality management, and a strong commitment to serve the community of PLWHA. The clarity of CTU and CRS organization and operations will ensure that it operates efficiently to perform clinical research at the highest standard, with the ability to rapidly respond to evolving opportunities.