This study will evaluate the safety, tolerability, and immunogenicity to four different HIV vaccines in healthy, HIV-uninfected adults. The vaccines include three DNA vaccines-DNA Nat-B env, DNA CON-S env, and DNA Mosaic env-and a vaccine called MVA-CMDR that may boost the immune response to the DNA vaccines.~The study will enroll healthy, HIV-uninfected participants aged 18 to 50 years. Participants will be randomly assigned to one of three groups and will receive either one of the experimental vaccine regimens or a placebo vaccine regimen. Group 1 participants will receive the DNA Nat-B env and MVA-CMDR vaccines or placebo. Group 2 participants will receive the DNA CON-S env and MVA-CMDR vaccines or placebo. Group 3 participants will receive DNA Mosaic env and MVA-CMDR vaccines or placebo.~All participants will receive one of their assigned vaccines at study entry (Month 0), and Months 1, 2, 4, and 8.~Total study duration will be either 3 years after enrollment (for participants in the United States) or 5 years after enrollment (for participants in Switzerland). For all participants, study visits will occur at study entry (Month 0), and Months 0.5, 1, 1.5, 2, 2.5, 4, 4.5, 8, 8.25, 8.5, 11, 13.75, and 14. After the last study visit, participants will be contacted annually by phone or e-mail for a total of 3 (U.S. participants) or 5 (Switzerland participants) years to answer questions about their health.~All study visits will include a physical exam, HIV risk reduction counseling, and an interview and/or questionnaire. Select study visits will include blood collection, urine and stool collection, HIV testing, an electrocardiogram (ECG), and a pregnancy test for participants who were born female. For participants receiving the MVA-CMDR vaccine, select study visits may also include an assessment of cardiac symptoms.
The purpose of this study is to evaluate the safety and immune response to three DNA vaccines and a MVA-CMDR vaccine that may boost the immune response to the DNA vaccines in healthy, HIV-uninfected adults.