This is a long-term follow-up study of people who are identified during acute or recent HIV infection and are being followed at clinical research sites associated with the Acute HIV Infection and Early Disease Research Program (AIEDRP). The purpose of this study is to collect data on the immunological and virologic responses that occur early in the course of HIV infection in treatment-naive and treatment-experienced HIV infected adults.

Study hypothesis: This study will examine the immunological responses that occur early in the course of HIV infection in treated and untreated individuals. The long-term follow-up of these subjects will help identify host immunological and genetic factors along with therapeutic strategies associated with control of viremia and delayed disease progression. In addition, this cohort will provide the recruiting mechanism to support future trials of therapy to restore immune function. Furthermore, this cohort will provide a population suitable to monitoring changing patterns in the transmission of drug resistant viral strains while also evaluating ongoing behavioral risk factors associated with HIV transmission.

This study will collect data on the immunological and virologic responses that occur early in the course of HIV infection in treated and untreated HIV infected adults to identify host immunological, virological, and therapeutic factors that influence disease progression. This study will also monitor changing patterns in the transmission of drug-resistant viral strains and evaluate ongoing behavioral risk factors associated with HIV infection.

Participants in this study will be followed for up to 10 years. During the first year of participation, study visits will occur approximately every 4 weeks for the first 12 weeks, then every 12 weeks thereafter, with a minimum of 8 study visits during the first year. Participants will be asked to complete a behavioral questionnaire at Week 8. After the first year of participation, there will be 4 visits per year. Blood collection and vital sign measurement will occur at each study visit.

Participants enrolled in this study are strongly encouraged to also enroll in the AIEDRP CORE01 study.

Inclusion Criteria:

• Documented acute or recent HIV infection as defined in the study protocol
• Willing to be followed longitudinally by this study

Treatment-naive and treatment-experienced HIV-infected adults