About 80 groups around the world are researching vaccines and some are now entering clinical trials.
The first human trial for a vaccine was announced in Seattle. Pharmaceutical companies Sanofi and GSK have teamed up to develop a vaccine
Australian scientists have begun injecting ferrets with two potential vaccines. It is the first comprehensive pre-clinical trial involving animals, and the researchers hope to test humans by the end of April
University of Oxford researchers are aiming to have a million doses of a vaccine by September, and are starting human trials