Adolescents who are displaced and living in shelters or in the streets constitute an extremely vulnerable population for acquisition of HIV infection worldwide. In the U.S., homeless youth, particularly African American Gay, Bisexual, and Transgendered Youth (GBTY), are very susceptible to substance abuse, juvenile justice contact, and acquisition of HIV and other sexually transmitted infections (STI). The displaced adolescent population is not generally amenable to routine clinic follow-up in hospital settings and potentially more easily identified through mobile outreach efforts. HIV prevalence in this group can be as high as 5.3%. While HIV incidence is unknown, high rates of concurrent exposures to other STIs, substance abuse, and survival sex suggest acute infection is likely high. Pediatric studies of HIV perinatally infected infants treated very early with potent antiretroviral therapy as well as studies of adult cohorts treated during acute infection, have shown that very early treatment of HIV is associated with control and decrease in viral reservoir burden, which is likely predictive of long term HIV control. Although early treatment has not yet been demonstrated to induce a functional cure, it has been associated with an extended period of complete viral quiescence, also known as HIV drug free remission. No studies of this kind have enrolled significant numbers of adolescents. Some studies suggest HIV reservoirs from adolescents who were recently HIV infected may be more pliable and responsive to early combined antiretroviral treatment (cART) than that of adults. Prolonged control of HIV through cART initiated following established HIV infection does not appear to impact viral reservoir size. HIV remission is not attainable in this scenario following treatment interruption, even after many years of undetectable plasma virus levels while on cART. We hypothesize that very early antiretroviral treatment of adolescents with acute HIV infection will be associated with decreased viral reservoir size, and viral reservoir size will be significantly different between adolescents with acute, recent or established HIV infection. To evaluate our hypothesis, we propose to capitalize on a current community-based strategy to initiate very prompt antiretroviral treatment many times the very day of diagnosis of HIV infection. Patients with newly diagnosed HIV infection will be offered antiretroviral treatment immediately or within a very short time by our collaborating clinical sites, and through the present study will be monitored periodically for assessment of virus load and HIV reservoir assays.