Researchers say an experimental Ebola vaccine appears safe and has triggered signs of immune protection in the first 20 volunteers to test it.
According to a study in the New England Journal of Medicine, the vaccine is designed to spur the immune system's production of anti-Ebola antibodies. Some of those given the vaccine developed antibodies within four weeks of getting the shots at the National Institutes of Health. Half of the test group received a higher-dose shot, and those people produced more antibodies.
The study also found that some people also developed a different set of virus-fighting immune cells, called T cells. National Institute of Allergy and Infectious Diseases director Dr. Anthony Fauci calls both types of immune responses "a promising factor."
The researchers reported no serious side effects.
Scientists are racing to develop ways to prevent or treat the Ebola virus. It has killed more than 5,600 people in West Africa, most of them in Guinea, Liberia and Sierra Leone.