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