Early safety trials of two vaccines against Ebola virus have started. Early results have uncovered few problems with the experimental vaccines, but these tests involve only a few hundred people as yet.
All the people who have received these vaccines are healthy volunteers. These trials are the first steps in human tests of a vaccine against Ebola virus. They are being done to determine if the vaccine is safe and to measure immune responses in the blood of the volunteers. Later trials will determine if the vaccines are effective in preventing an infection by Ebola virus.
Safety trials of one vaccine are being held in the United States, the United Kingdom, Mali, and Switzerland. This vaccine, ChAD3, is a product of GlaxoSmithKline and the U.S. National Institutes of Health. Initial results from the first human trial of a version of this vaccine, which is designed to protect against the Zaire and Sudan strains of Ebola, showed promising safety and immunologic findings. A second trial is underway to determine if a booster shot of another vaccine can help increase immune responses.
Another vaccine, VSV-EBOV, is being developed by NewLink Genetics and Merck. Tests of this vaccine are underway in Switzerland. Some recipients of the vaccine have reported mild to moderate inflammation at the injection site for a few days, a reaction that was not unexpected.
VSV-EBOV uses an Ebola virus protein spliced into a vesicular stomatitis virus. ChAD3 uses a modified chimpanzee adenovirus
The largest outbreak of Ebola in history is still underway in Guinea, Sierra Leone, and Liberia in Western Africa. The hemorrhagic virus has infected more than 17,000 people and killed more than 6,000, according to the U.S. Centers for Disease Control and Prevention. There are five subspecies of the Ebola virus
Several pharmaceutical companies have escalated their efforts to develop vaccines against the Ebola virus. A vaccine is expected to be ready for at least some use in 2015.