inclusion criteria: all subjects: adult male and female aged ≥ 18 to < 65 years at screening for cohorts 1 and 2 and adult male or female aged ≥ 65 to < 85 years at screening for cohort 1 only. body mass index (bmi) of 17 to 40 kg/m². provides informed consent prior to study participation and is willing to comply with study procedures, including potential home visits. women of child-bearing potential must agree not to have sexual intercourse with men, or must consistently use an agreed method of contraception from at least 21 days prior to enrolment in the study, through 6 months after the last vaccination. hiv-negative subjects only: documentation of hiv-negative test result by a method approved in south africa. healthy at study screening, as determined by the investigator. hiv-positive subjects only: documentation of hiv-positive test result by a method approved in south africa. receiving highly active antiretroviral therapy (haart) and has been using the same regimen for at least 8 weeks before screening. changes in antiretroviral dosage within 8 weeks of entering the study are allowed, as are exchanges in pharmacological formulations. medically stable at screening, as determined by the investigator, and free of opportunistic infections in the 1 year prior to first study vaccination. have a hiv-1 viral load < 1000 copies/ml within 45 days of randomization in the study.

inclusion criteria: all subjects: adult male and female aged ≥ 18 to < 65 years at screening for cohorts 1 and 2 and adult male or female aged ≥ 65 to < 85 years at screening for cohort 1 only. body mass index (bmi) of 17 to 40 kg/m². provides informed consent prior to study participation and is willing to comply with study procedures, including potential home visits. women of child-bearing potential must agree not to have sexual intercourse with men, or must consistently use an agreed method of contraception from at least 21 days prior to enrolment in the study, through 6 months after the last vaccination. hiv-negative subjects only: documentation of hiv-negative test result by a method approved in south africa. healthy at study screening, as determined by the investigator. hiv-positive subjects only: documentation of hiv-positive test result by a method approved in south africa. receiving highly active antiretroviral therapy (haart) and has been using the same regimen for at least 8 weeks before screening. changes in antiretroviral dosage within 8 weeks of entering the study are allowed, as are exchanges in pharmacological formulations. medically stable at screening, as determined by the investigator, and free of opportunistic infections in the 1 year prior to first study vaccination. have a hiv-1 viral load < 1000 copies/ml within 45 days of randomization in the study.

inclusion criteria: all subjects: - 18 to 64 years at screening for cohort 2 and 18 to 84 years at screening for cohort 1. - body mass index (bmi) of 17 to 40 kg/m². - provides informed consent prior to study participation and is willing to comply with study procedures, including potential home visits. - women of child-bearing potential must agree not to have sexual intercourse with men, or must consistently use an agreed method of contraception from at least 21 days prior to enrolment in the study, through 6 months after the last vaccination. hiv-negative subjects only: - documentation of hiv-negative test result by a method approved in south africa. - healthy at study screening, as determined by the investigator. hiv-positive subjects only: - documentation of hiv-positive test result by a method approved in south africa. - receiving highly active antiretroviral therapy (haart) and has been using the same regimen for at least 8 weeks before screening. changes in antiretroviral dosage within 8 weeks of entering the study are allowed, as are exchanges in pharmacological formulations. - medically stable at screening, as determined by the investigator, and free of opportunistic infections in the 1 year prior to first study vaccination. - have a hiv-1 viral load < 1000 copies/ml within 45 days of randomization in the study.

inclusion criteria: all subjects: - 18 to 64 years at screening for cohort 2 and 18 to 84 years at screening for cohort 1. - body mass index (bmi) of 17 to 40 kg/m². - provides informed consent prior to study participation and is willing to comply with study procedures, including potential home visits. - women of child-bearing potential must agree not to have sexual intercourse with men, or must consistently use an agreed method of contraception from at least 21 days prior to enrolment in the study, through 6 months after the last vaccination. hiv-negative subjects only: - documentation of hiv-negative test result by a method approved in south africa. - healthy at study screening, as determined by the investigator. hiv-positive subjects only: - documentation of hiv-positive test result by a method approved in south africa. - receiving highly active antiretroviral therapy (haart) and has been using the same regimen for at least 8 weeks before screening. changes in antiretroviral dosage within 8 weeks of entering the study are allowed, as are exchanges in pharmacological formulations. - medically stable at screening, as determined by the investigator, and free of opportunistic infections in the 1 year prior to first study vaccination. - have a hiv-1 viral load < 1000 copies/ml within 45 days of randomization in the study.