Study to Compare the Immunogenicity and Safety of Two HIV Preventive Vaccinations in Healthy Volunteers

Inclusion Criteria: * age between 18 and 55 years on the day of screening * available for follow-up for the duration of the study (78 weeks from screening) * able to give written informed consent * at low risk of HIV and willing to remain so for the duration of the study low risk of HIV infection defined as: * no history of injecting drug use in the previous ten years * no gonorrhoea or syphilis in the last six months * no high risk partner (e.g. injecting drug use, HIV positive partner) either currently or within the past six months * no unprotected anal intercourse in the last six months, outside a relationship with a regular partner known to be HIV negative * no unprotected vaginal intercourse in the last six months outside a relationship with a regular known/presumed HIV negative partner * willing to undergo a HIV test * willing to undergo a genital infection screen * if heterosexually active female, using an effective method of contraception with partner (combined oral contraceptive pill; injectable contraceptive; IUCD; consistent record with condoms if using these; physiological or anatomical sterility in self or partner) from 14 days prior to the first vaccination until 4 months after the last, and willing to undergo urine pregnancy tests prior to each vaccination * if heterosexually active male, using an effective method of contraception with their partner from the first day of vaccination until 4 months after the last vaccination * for French volunteers only : * subjects registered in French Health ministry computerised file and authorised to participate in a clinical trial * subjects covered by Health Insurance * subjects included in the ANRS vaccine research network of volunteers Exclusion Criteria: * pregnant or lactating * clinically relevant abnormality on history or examination including history of grand-mal epilepsy; severe eczema; allergy to eggs or gentamicin; severe allergic diseases; liver disease with inadequate hepatic function; haematological, metabolic or gastrointestinal disorders; uncontrolled infection; autoimmune disease, immunodeficiency or use of immunosuppressives in preceding 3 months * receipt of live attenuated vaccine within 60 days or other vaccine within 14 days of enrolment * receipt of blood products or immunoglobin within 4 months of screening * participation in another trial of a medicinal product, completed less than 30 days prior to enrolment * history of severe local or general reaction to vaccination defined as * local: extensive, indurated redness and swelling involving most of the anterolateral thigh or the major circumference of the arm, not resolving within 72 hours * general: fever \>= 39.5oC within 48 hours; anaphylaxis; bronchospasm; laryngeal oedema; collapse; convulsions or encephalopathy within 72 hours * HIV 1/2 positive or indeterminate on screening * positive for hepatitis B surface antigen, hepatitis C antibody or serology indicating active syphilis requiring treatment * positive for DNA/ANA antibodies at titre considered clinically relevant by immunology laboratory * grade 1 or above routine laboratory parameters (see section 4.1.4 \& appendix 4 for definitions) Note of clarification 18th april 2008: hyperbilirubinemia has to be considered as an exclusion criterion only when confirmed to be conjugated bilirubinemia * unlikely to comply with protocol