Recent studies at the AIDS vaccine units have shown the safety of two candidate HIV vaccines, HIVAC-1e and gp160. Specific questions to be addressed in this part of the study include: Does combination vaccination result in a synergistic (added) response not predicted by just the addition of a second vaccination, and does this synergism depend on the unique priming effect of a vaccinia recombinant, or will any combination do?

Volunteers will be randomized to one of four groups. Group A (20 volunteers) will receive gp160 (VaxSyn) followed two months later by a repeat dose. Group B (20 volunteers) will receive VaxSyn followed two months later by HIVAC-1e. Group C (20 volunteers) will receive HIVAC-1e followed two months later by VaxSyn. Group D (10 volunteers) will receive HIVAC-1e followed two months later by HIVAC-1e. For volunteers in Groups A, B, and C who do not react to the initial vaccination, a second attempt to obtain a reaction may be made 7 or more days following the initial inoculation. Per addendum, two additional booster inoculations are given: one at 6 months or later post initial inoculation (Groups A, C, and D receive VaxSyn and Group B receives HIVAC-1e) and another at 12 months or later (all Groups receive VaxSyn).

Inclusion Criteria

• Volunteers must be healthy adults without high-risk behavior for HIV-1 infection and with history of smallpox vaccination more than 5 years prior to enrollment.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms and conditions are excluded:

• Identifiable high-risk behavior for HIV infection including active intravenous drug use and multiple sexual partners or sexual contact with high-risk partners within the past 6 months.
• Eczema, active or within the past year.
• Household contact with someone who is pregnant.
• Household contact with children less than 12 years old.
• Household contact with anyone with eczema.
• Household contact with anyone with immunodeficiencies.
• Hypersensitivity to insects.
• Medical or psychiatric conditions that would make compliance unlikely.
• Evidence of depression.

Patients with the following prior conditions are excluded:

• History of immunodeficiency or chronic illness or use of immunosuppressive medications.
• Blood or blood product transfusion within previous six months.
• Eczema, active or within the past year.
• Prior receipt of experimental HIV vaccine. [Specific other requirements are stated elsewhere in the record.]

Prior Treatment:

Excluded within 6 months prior to study entry:

• Blood or blood product transfusions.

Risk Behavior:

Excluded:

• Active intravenous drug use.
• Syphilis, gonorrhea, or any sexually transmitted diseases including chlamydia or pelvic inflammatory disease within the past 6 months.
• More than 2 sexual partners in the past 6 months or sexual contact with a high-risk partner.