The worldwide HIV/AIDS epidemic may only be controlled through development of a safe and effective vaccine that will prevent HIV infection. This study will evaluate the safety and immunogenicity of an experimental adenovirus-vectored multiclade HIV vaccine, VRC-HIVADV014-00-VP, followed with or without a similarly structured DNA plasmid HIV vaccine, VRC-HIVDNA016-00-VP. The DNA in both vaccines codes for proteins from HIV subtypes A, B, and C, which together represent 90% of new HIV infections in the world. HIV uninfected volunteers will be recruited in the East African nations of Kenya, Tanzania, and Uganda.~This study will comprise two parts, 1 and 2. Part 1 will enroll 144 participants who will be randomly assigned to one of four different groups:~Group 1A participants will receive a low dose of the adenovirus-vectored HIV vaccine or placebo at study entry.~Group 1B participants will receive a higher dose of the adenovirus-vectored HIV vaccine or placebo at study entry.~Group 1C will receive the DNA plasmid vaccine or placebo at study entry and Days 28 and 56. They will also receive either a low dose of the adenovirus-vectored HIV vaccine or placebo at Day 168.~Group 1D will receive the DNA plasmid vaccine or placebo at study entry and Days 28 and 56. They will also receive either a higher dose of the adenovirus-vectored HIV vaccine or placebo at Day 168.~Enrollment into Part 2 (Groups 2A and 2B) will begin after the completion of the safety data evaluation of Groups 3 and 4 and after Part A has been fully enrolled. Group 2A participants will receive the DNA plasmid vaccine or placebo at study entry and Days 28 and 56. They will also receive either a low dose of the adenovirus-vectored HIV vaccine or placebo at Day 168.~There will be 11 study visits over 14 to 16 months for Parts 1 and 2. All study visits will include a physical exam, medical and medication history, vital signs measurement, lymph node assessment, HIV and pregnancy counseling, and blood and urine collection. A home visit will also occur at study entry. A 3-day diary card to report side effects will be completed by participants at study entry and on Days 28, 56, 168, and 210.~There will be 14 study visits for Groups 3, 4, and 5; these visits will include the same tests and assessments as for Groups 1 and 2.~As per an amendment (dated December 19, 2005), follow-up for this study will be extended. The purpose for this extension is to examine in greater depth the efficacy of the vaccine. Specifically, investigators will be exploring whether there is a persistent immune response in participants who received the vaccine as well as if new or boosted responses to the adenovirus vaccine are persistent. The extended follow-up will last for 2 years with clinic visits every 4 months. During visits blood will be drawn for laboratory tests, including HIV testing. Participants will also be informed of ways to reduce their risk of contracting HIV. Two weeks after each visit, participants will be asked to come to the study site for a short post HIV test counseling visit. There will be a total of 6 visits per year, 3 follow-up visits, and 3 post HIV test counseling visits. There will be no more vaccinations.
The purpose of the study is to determine the safety of and immune response to an investigational HIV vaccine, VRC-HIVDNA016-00-VP, and a vaccine booster, VRC-HIVADV014-00-VP, in HIV uninfected adults from Kenya, Tanzania, and Uganda.