At the time when Ebola virus disease (EVD) outbreak began in December 2013 in western Africa, there were no vaccinations available. Research has allowed the development of candidate vaccines against Ebola in recent years. Two such candidate vaccines have been put through a placebo-controlled phase 2 clinical trial in Liberia. The study included 1,500 adults and the results of the large randomized study are published in the New England Journal of Medicine.