• Local and systemic reactogenicity signs and symptoms
  
• laboratory measures of safety
  
• adverse experiences
  

• Immunogenicity endpoints
  
• social impacts
  

HIV-1 subtype C is the prevailing subtype of HIV found in sub-Saharan Africa and is primarily responsible for the HIV/AIDS epidemic in southern Africa. Thus, development of a preventive subtype C vaccine is critically important in controlling the spread of HIV in this part of the world. This study will determine the safety and immunogenicity of an alphavirus replicon HIV-1 subtype C gag vaccine, AVX101, in HIV uninfected adults. This vaccine utilizes a propagation-defective replicon vector system derived from an attenuated strain of Venezuelan Equine Encephalitis (VEE) virus. The vaccine replicon expresses the gag gene from a South African subtype C isolate of HIV-1. Participants will be recruited in the United States, South Africa, and Botswana.

The study will last for 1 year. Participants will be enrolled sequentially, from lowest to highest dose of vaccine, into one of four groups. Groups will begin enrollment only following safety review of the previous group. Participants will be randomly assigned to receive active vaccine or placebo. During the study, participants will receive either 3 injections of one of four possible doses of the vaccine or 3 injections of placebo. Injections will be given at study entry and at Days 28 and 84. At screening, participants will undergo medical history assessment, a complete physical, HIV testing and counseling, and blood and urine collection; they will also be interviewed and asked to complete a questionnaire. After screening, there will be 8 study visits; the visits will occur at Days 14, 28, 42, 84, 98, 168, 273, and 364. Participants will be interviewed and asked to fill out a questionnaire at each study visit; participants will undergo a physical, additional HIV testing and counseling, and blood and urine collection at selected visits.