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