A Phase I, Multicenter, Randomized Trial to Evaluate the Safety and Immunogenicity of a Recombinant Vaccinia-HIV Envelope Vaccine (HIVAC-1e) in Combination With a Panel of Subunit Recombinant HIV Envelope Vaccines in Vaccinia-Naive Individuals

Primary: To determine whether combination vaccination, i.e., priming with a vaccinia recombinant-containing HIV envelope (HIVAC-1e) followed by boosting with a recombinant subunit envelope protein (gp160 or gp120), provides enhanced immunogenicity compared to subunit vaccination with the individual recombinant envelope proteins only. To compare the relative immunogenicity of a panel of HIV envelope subunit vaccines when administered as boosters following recombinant HIV-vaccinia priming. To evaluate the relative immunogenicity of one versus two doses of recombinant HIV-vaccinia prior to the subunit protein boost.

Secondary: To examine the safety of administering the individual subunit vaccines in combination with the HIV envelope vaccinia recombinant, and to extend the population to whom these proteins have been administered.

Previous studies suggest that priming with an HIV-vaccinia recombinant followed by boosting with subunit envelope proteins offers the most promising strategy to date for a safe and immunogenic vaccine in humans. This study will further examine the combination vaccine approach and define an optimal prime-boost strategy.