The applicant organization, the Medical Research Foundation of Trinidad and Tobago (MRFTT), has been conducting retroviral research for the past 17 years and is currently one of the HVTN sites conducting a Phase II HIV vaccine trial (HIVNET 026). The overall aim of this project is to conduct HIV/AIDS prevention and treatment intervention studies to fill the gaps in available knowledge and to provide scientific and public health solutions to the HIV epidemic in Trinidad and Tobago, a middle-income developing country. Our hypothesis is that the Trinidad & Tobago share attributes with many countries in the Caribbean region and world that make such knowledge applicable to these countries. The major aim of this RO3 submission is to develop a research program responsive to the research needs of the HIV/AIDS epidemic in Trinidad and Tobago and to the CIPRA process. During the execution period there will be a comprehensive assessment of the site development needs, site infrastructure and critical clinical and laboratory capacity to perform relevant HIV/AIDS prevention and treatment intervention research, including clinical trials. The final CIPRA cooperative agreement application will be developed and submitted during this period. The MRF1T has throughout its years of research established collaborations locally, regionally and internationally and during the RO3 period these collaborations will be further strengthened. The Caribbean Epidemiology Center (CAREC) has been a research and implementation partner since 1984, and laboratory support for the majority of the studies conducted here has resided at CAREC. CAREC also provides the opportunity to disseminate the findings of these intervention studies to the wider Caribbean. The MRF1T has conducted all studies with the cooperation and collaboration of the Ministry of Health (MOH), and through the CIPRA application, the MRFTT will further enhance its relationship with the MOH in meeting the challenges of the HIV/AIDS epidemic in Trinidad and Tobago and in the development of appropriate prevention and treatment intervention public health programs. The MRF1T will also draw on its ties to local NGO's and its international collaborations with the Institute of Human Virology of the University of Maryland, Baltimore and Duke University, North Carolina in the development and conduct of the planned research.