Evaluation of a New Ebola Vaccine Using a Short-interval Prime-boost Vaccination

This is a clinical trial in which healthy volunteers will be administered two experimental Ebola vaccines: ChAd3-EBO Z and MVA-EBO Z. Two groups of volunteers will be vaccinated with both vaccines one after the other in a prime/boost regimen. All ChAd3-EBO Z doses are 2.5 x 10\^10 - 3.7 x 10\^10 vp and all MVA-EBO Z doses are 1.0 x 10\^8 pfu. All volunteers will receive a ChAd3-EBO Z priming vaccine and a MVA-EBO Z boosting vaccine 7 days later. The site of administration of the MVA-EBO Z vaccine differs between the two groups: Group 1 will receive the MVA-EBO Z vaccine in the same arm as the ChAd3-EBO Z vaccine. Group 2 will receive the MVA-EBO Z vaccine in the opposite arm from the ChAd3-EBO Z vaccine. The study will assess the safety of the vaccinations, and the immune responses to vaccination. Immune responses are measured by tests on blood samples. The ChAd3-EBO Z and MVA-EBO Z vaccines are called viral vectored vaccines. They are made from viruses which are modified so that they cannot multiply. The viruses have extra DNA in them so that after injection, the body makes Ebola proteins (but Ebola does not develop), so that the immune system builds a response to Ebola without having been infected by it. Healthy volunteers will be recruited in Dakar, Senegal. The study will be funded by GSK.