An experimental vaccine against the Ebola virus has proved effective and well-tolerated in the first human trial of a candidate Ebola drug. Researchers from the National Institutes of Health found that the vaccine induced a strong immune response in all twenty people who received it and led to the production of certain immune cells thought to be key in protecting against Ebola. “All in all, I would say it was a successful phase one study,” says Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases (NIAID), which developed the drug in collaboration with GlaxoSmithKline. The next steps are to move ahead with a larger efficacy trial in West Africa. The vaccine, which contains genetic material from two Ebola strains (Sudan and Zaire) was administered to ten individuals at a low dose and and to a further ten at a high dose. Within four weeks of receiving the injections, all twenty volunteers had produced anti-Ebola antibodies. The antibody level was highest among those who received the higher dose. Importantly, further testing revealed that the vaccine had induced the production of CD8 T cells, which have been shown in animal studies to play an important role in protecting against Ebola. “We know from previous studies in non-human primates that CD8 T cells played a crucial role in protecting animals that had been vaccinated with this NIAID/GSK vaccine and then exposed to otherwise lethal amounts of Ebola virus,” says Julie Ledgerwood, the trial’s principal investigator. She adds: "The size and quality of the CD8 T cell response we saw in this trial are similar to that observed in non-human primates vaccinated with the candidate vaccine" The vaccine was also safe and caused no serious adverse effects in any of the participants. “Based on these positive results from the first human trial of this candidate vaccine, we are continuing our accelerated plan for larger trials to determine if the vaccine is efficacious in preventing Ebola infection,” says Fauci. Source
