Immune Response to a Therapeutic HIV Vaccine Followed by Treatment Interruption in Patients With Acute or Recent HIV Infection

Inclusion Criteria: * Initiated HAART within 30 days of an acute or recent HIV-1 infection diagnosis. More information on this criterion can be found in the protocol. * Initiated HAART within 30 days of documented acute or recent HIV-1 infection without interruption for more than 7 days * Sustained viral suppression, defined as a viral load of 500 copies/mL or less 12 months prior to baseline with an undetectable HIV-1 RNA viral load between 60 to 7 days prior to baseline * CD4 count of 450 cells/mm3 or more OR 35% or more between 60 to 14 days prior to baseline * Ad5 neutralizing antibody titer of 200 or less at screening * Willing to follow all study procedures and schedules * Willing to interrupt HAART for at least 24 weeks following completion of the vaccination stage * Negative for hepatitis B surface antigen (HBsAg) at screening * Willing to use acceptable forms of contraception * Infected with HIV-1 subtype B, if this information is available Exclusion Criteria: * Virologic relapse, defined as 2 consecutive measurements of viral load of 500 copies/mL or more at least 7 days apart within 12 months of baseline visit * Received more than 7 days of continuous HAART other than that received within 16 days of acute or recent HIV-1 infection. Participants who received HAART as part of post-exposure prophylaxis (PEP) more than 6 months prior to the start of initial HAART may be eligible, provided that they did not acquire HIV-1 infection from the event that required PEP. * History of anaphylaxis or allergy to vaccine components, including Tris buffer, magnesium chloride, and polysorbate 80 (Tween) * History of clinically significant heart, lung, kidney, liver, pancreatic, gastrointestinal, or neurological disease that, in the opinion of the study investigator, may interfere with the study * Contraindication to intramuscular (IM) injection, such as anticoagulant therapy or thrombocytopenia * Receipt of any immune globulin or blood products within 3 months prior to baseline * Receipt of any live vaccine within 30 days prior to baseline or any inactivated vaccine within 14 days prior to baseline * Previous receipt of any HIV vaccine. Participants that were documented to have received only placebo are not excluded. * History of any AIDS-defining illness. If a participant's sole AIDS-defining illness is Kaposi's sarcoma limited to the skin and is not anticipated to require systemic chemotherapy, that participant is not excluded. * Currently receiving drugs or biologics not approved by the Food and Drug Administration (FDA) other than investigational HIV medications * Current or past participation in other studies that might alter the participant's response to the study vaccination * Use of any immunomodulatory agents, including but not limited to interleukin-2 (IL-2), granulocyte/macrophage-colony stimulating factor (GM-CSF), and systemic corticosteroids, within 30 days prior to baseline * Active alcohol or substance use that, in the investigator's opinion, may interfere with the study * Any other criteria or condition that, in the investigator's opinion, may interfere with the study * Unwilling or unable to contribute to the planned peripheral blood mononuclear cell (PBMC) blood collection * Pregnancy or breastfeeding