A Study to Test Three Experimental HIV Vaccines in Healthy Adults.

HIV-CORE 006 is a Phase 1 double-blind placebo-controlled trial, in which the mosaic immunogens are delivered by a prime-boost regimen of non-replicating simian adenovirus followed by non-replicating poxvirus MVA. Volunteers will be randomised to receive either the vaccine regimen or placebo at 2 vaccination visits 4 weeks apart. The vaccine regimen consists of a single mosaic prime ChAdOx1.tHIVconsv1 (C1) and a dual boost of MVA.tHIVconsv3 (M3) and MVA.tHIVconsv4 (M4) administered simultaneously. The trial will recruit healthy African adults 18-50 years of age, who are HIV-uninfected and at low risk of HIV infection. The trial is designed to enrol 88 healthy men and women, who will be randomised to receive either the vaccine regimen or placebo in a ratio of 72:16: * Vaccine Arm (ChAdOx1.tHIVconsv1 prime followed by MVA.tHIVconsv3 and MVA.tHIVconsv4 boost at 4 weeks after enrolment); 72 vaccine recipients; * Placebo Arm; 16 recipients To maintain blinding, all volunteers will receive two injections with half dose into the deltoid region of each arm of ChAdOx1.tHIVconsv1 or placebo at enrolment, and two injections (MVA.tHIVconsv3 or placebo into one deltoid region and MVA.tHIVconsv4 or placebo into the other) at 4 weeks after enrolment. The primary goal of assessing safety and immunogenicity will be served by weighting the randomisation toward vaccinees.