Safety of and Immune Response to an HIV-1 Vaccine Boost (VRC-HIVADV014-00-VP) in HIV Uninfected Adults Who Participated in HVTN 052

The worldwide HIV epidemic highlights the importance of developing an affordable, globally successful vaccine for HIV prevention. The VRC-HIVADV014-00-VP adenoviral vector vaccine used in this study was developed to stimulate strong virus-specific CD8 cytotoxic T-lymphocyte (CTL) responses thought to be crucial in an effective preventive HIV vaccine. The purpose of this study is to determine the safety and immunogenicity of a VRC-HIVADV014-00-VP vaccine boost given to healthy, HIV uninfected individuals who participated in HVTN 052, which evaluated the VRC-HIVDNA009-00-VP DNA plasmid vaccine. In that study, participants received either 3 injections of vaccine, 2 injections of vaccine and 1 injection of placebo, or 3 injections of placebo over a 2-month period. This study will last one year. Participants will be randomly assigned to receive vaccine boost or placebo by intramuscular injection. The injections will be given 6 to 9 months after each participant's first HVTN 052 study injection, preferably as close to 6 months after the first HVTN 052 injection as possible. After a screening visit, study visits will occur at enrollment (when the injection will be given), at Week 2, and at Months 1, 3, 6, and 12. Blood collection, physical exam, and medication assessment will occur at every study visit; urine collection will occur at selected visits.