NOTE: This study has stopped enrolling new participants, and all study vaccinations for currently enrolled participants have been stopped.~This study will evaluate the safety and immune response to three different vaccine schedules of a DNA HIV vaccine (DNA-HIV-PT123) followed by a NYVAC HIV vaccine boost (NYVAC-HIV-PT1 and NYVAC-HIV-PT4) in healthy, HIV-uninfected adults. Study researchers will also evaluate the safety of administering the HIV vaccine on a shorter administration schedule.~This study will take place in two parts. Participants in Part A of the study will receive the DNA HIV vaccine on a faster schedule than usual: at Days 0, 14, and 28. At study entry, participants will undergo a physical examination, HIV risk reduction counseling, and interviews and questionnaires. Female participants will take a pregnancy test. Study visits will occur at Days 0, 14, 28, 42, 140, and 224. These study visits will include some of the same procedures performed at study entry, as well as blood collection, urine collection, and HIV testing.~Study researchers will evaluate participant data from Part A of the study, and if there are no safety concerns, they will enroll participants into Part B of the study. Participants in Part B of the study will be randomly assigned to one of three groups, and within each group, some participants will be randomly assigned to receive placebo vaccine. Participants will receive DNA HIV vaccine or placebo on Days 0, 14, and 28 (Group 2); or Days 0 and 28 (Group 3); or Days 0, 28, and 56 (Group 4). The NYVAC HIV vaccine boost will be administered at Day 84 (Groups 2 and 3) or 140 (Group 4). Participants in Part B of the study, in Groups 2 and 3, will attend study visits at Days 0, 14, 28, 42, 84, 98, 168, and 273. Participants in Part B in Group 4 will attend study visits at Days 0, 14, 28, 42, 56, 70, 140, 154, 224, and 334. Participants in Part B of the study will undergo the same study procedures that occurred in Part A of the study, with the addition of a cardiac symptoms assessment performed at some study visits. Participants in Part B who received the NYVAC vaccine or its placebo prior to study vaccinations being stopped will be contacted by phone or e-mail once a year for 5 years after they enrolled into the study for follow-up health monitoring.
NOTE: This study has stopped enrolling new participants, and all study vaccinations for currently enrolled participants have been stopped.~Currently, there are no vaccines approved for the prevention of HIV infection, but there are many clinical trials taking place that are studying experimental HIV vaccines. The purpose of this study is to evaluate the safety and tolerability of three different HIV vaccine schedules in healthy, HIV-uninfected adults.