Partnership for Research on Ebola Vaccines in Liberia (PREVAIL)

Overview

Background: \- Ebola virus disease (EVD) affects many people in Liberia and other countries in West Africa. It is caused by the Ebola virus and makes people sick with fever, headache, vomiting, diarrhea, rash, and bleeding. About half the people with EVD die. There is no approved treatment for it. Researchers are studying two Ebola vaccines. The vaccines do not cause Ebola. Objectives: \- To study the safety and efficacy of two Ebola vaccines. Eligibility: \- Adults 18 and older who live in Liberia and are at risk for Ebola infection but have never had Ebola. Design: * Participants will give information including birthdate, gender, occupation, and location of home. They will give contact information for themselves and 2 alternate contacts. They will give a history of their contact with people with Ebola. Some participants may have a physical. They may have blood taken. * Participants will be injected with either an Ebola vaccine or a placebo with a needle in the upper arm. The placebo is a salt solution. * Participants will have blood taken. * Participants will be watched for 30 minutes. * Participants will return to the clinic 1 week and 1 month after they get the shot. They will have blood taken. * After that, participants will be contacted monthly to discuss how they are feeling. They may be contacted by phone, may visit the clinic, or may have a home visit. * The study ends 8-12 months after participants get the shot. If one of the vaccines works against Ebola and does not have many side effects, participants can get the vaccine if they did not get it in the study.

Ebola virus disease (EVD) in West Africa is spreading rapidly, and there is a critical need for a vaccine to prevent EVD. There are two candidate Ebola virus vaccines, the chimpanzee adenovirus 3 (ChAd3-EBO Z)-based vaccine and the Vesicular Stomatitis virus (VSVdeltaG-ZEBOV)-based vaccine. This study will evaluate both of these vaccines in a randomized, double-blind, controlled, 3-arm study in Liberia. Each vaccine will be compared against the same active control. Because there are limited data on the safety of these vaccines, the initial phase (phase 2) of the study will include the collection of more detailed data on safety and will define the immune response elicited by each vaccine in the first 600 volunteers. With the decline in new cases of Ebola virus infection the phase 3 component was no longer deemed to be feasible and, following safety, ethical and FDA approve/concurrence, the study was amended to a more robust, 1,500 person phase 2 design. With the amendment to only a phasae 3 study the endpoint reverted to the phase 2 endpoint of safety and immunogenicity. Participants aged 18 year and older will be enrolled at health clinics in Monrovia, Liberia over 4 months. A single dose of the assigned agent will be administered. Participants in phase 2 will undergo blood draw and assessment of adverse events (AEs) and signs and symptoms of Ebola infection at 1 week and 1 month after vaccination, and monthly assessment of AEs and signs and symptoms of Ebola thereafter. Participants in phase 3 will undergo monthly assessment of AEs and signs and symptoms of Ebola infection after vaccination. All participants will be followed for 8 to 12 months. This clinical trial to evaluate vaccine efficacy will provide an accurate assessment of the benefits and risks associated with each candidate vaccine and inform policy on wider scale vaccination in other countries.