Effectiveness of and Immune Response to HIV Vaccination Followed by Treatment Interruption in HIV Infected Patients

HIV vaccines may help the immune systems of HIV infected patients better control the virus. The goal of this study is to determine whether patients on anti-HIV medications can stop taking those medications if they receive an HIV vaccine. While taking anti-HIV medications, participants will receive either an HIV vaccine or a placebo. Participants will then stop taking their anti-HIV medications and the study will compare the viral loads of participants who received the vaccine with the viral loads of participants who received the placebo. Primary study hypotheses: 1)The Week 12 and Week 16 post-ART interruption geometric mean HIV-1 RNA levels will be lower among participants who had received MRK Ad5 vaccine prior to ART interruption than among participants who received placebo; 2) the time averaged area under the curve of the log10 HIV-1 RNA copies/ml versus day function in the 16 week post-ART interruption step will be lower among participants who received the MRK Ad5 vaccine prior to ART interruption than among participants who receive placebo.