Two investigational Ebola vaccines have been tested and proved to be immunogenic and well-tolerated among 1,500 participants in a randomized, placebo-controlled clinical trial.
The trial, conducted in Liberia, received sponsorship from the National Institute of Allergy and Infectious Diseases (NIAID) and a partnership between the U.S. and Liberia.
Originally, the scientists planned on having 28,000 volunteers for a Phase 3 trial. This initial plan was revised because of the decrease in Ebola cases; there were not enough volunteers who had Ebola infections. Instead, the trial involved 1,500 men and women age 18 and older. None had any history of Ebola. The volunteers were divided into three groups of 500 people. Two groups received a respective vaccine or a saline injection.
The two vaccines, rVSV-ZEBOV and cAd3-EBOZ, are designed differently. The first carries the Ebola virus and its genetic material with the vesicular stomatitis virus. The second carries the virus with a chimpanzee-derived cold virus.
The trial, called PREVAIL I, was recently presented at the Conference on Retroviruses and Opportunistic Infections by Dr. Fatorma Bolay, one of the co-principal investigators and the director of the Liberian Institute for Biomedical Research.