The purpose of this study is to test the safety of and immune response to an HIV-1 vaccine, VRC-HIVADV014-00-VP, when given as a vaccine booster to 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.

Inclusion Criteria:

• Previously enrolled in and have completed all 3 study vaccine injections for HVTN 052
• Understanding of vaccination procedure
• Good general health
• HIV uninfected
• Hepatitis B surface antigen negative
• Anti-hepatitis C virus (HCV) antibody negative, or negative for HCV PCR if the anti-HCV is positive
• Willing to use acceptable forms of contraception

Exclusion Criteria:

• Immunosuppressive medications within 168 days prior to study
• Blood products within 120 days prior to study
• Immunoglobulin within 60 days prior to study
• Live attenuated vaccines within 30 days prior to study
• Investigational research agents within 30 days prior to study
• Medically indicated subunit or killed vaccines within 14 days prior to study
• Allergy shots within 30 days prior to study
• Current anti-tuberculosis prophylaxis or therapy
• Anaphylaxis or other serious adverse reactions to vaccines. A person who had an adverse reaction to pertussis vaccine as a child is not excluded.
• Autoimmune disease or immunodeficiency
• Active syphilis infection
• Unstable asthma (e.g., daily symptoms; use of oral or orally inhaled corticosteroids or other treatments; emergent care, urgent care, hospitalization, or intubation during the past 2 years)
• Diabetes mellitus. A participant with past gestational diabetes is not excluded.
• Thyroid disease, including removal of thyroid and diagnoses requiring medication. A participant not requiring thyroid medication during the last year is not excluded.
• Serious angioedema. A participant who has had an episode of angioedema over 3 years prior to the study, and has not required medications for at least 2 years, is not excluded.
• Uncontrolled hypertension
• Diagnosis of bleeding disorder
• Malignancy, except those with a surgical excision that has a reasonable assurance of sustained cure and/or is unlikely to recur during the period of the study
• Seizure disorder requiring medication within the last 3 years
• Absence of the spleen
• Mental illness that would interfere with compliance with the protocol
• Pregnancy or breastfeeding