The 2014–2015 Ebola epidemic in western Africa was the longest <span class="attribute-to-highlight medbox">and</span> most deadly Ebola epidemic in history, resulting in 28,616 cases <span class="attribute-to-highlight medbox">and</span> 11,310 deaths in Guinea, Liberia, <span class="attribute-to-highlight medbox">and</span> Sierra Leone. The Ebola virus has been known since 1976, when two separate outbreaks were identified in the Democratic Republic of Congo (then Zaire) <span class="attribute-to-highlight medbox">and</span> South Sudan (then Sudan). However, because all Ebola outbreaks prior to that in West Africa in 2014–2015 were relatively isolated <span class="attribute-to-highlight medbox">and</span> of short duration, little was known about how to best manage patients to improve survival, <span class="attribute-to-highlight medbox">and</span> there were no approved therapeutics or vaccines. When the World Heath Organization declared the 2014-2015 epidemic a public health emergency of international concern in August 2014, several teams began conducting formal clinical trials in the Ebola affected countries during the outbreak.