While some people do fight off the disease on their own, in the case of the two Americans, an experimental serum may have saved their lives. As Dr. Kent Brantly and missionary Nancy Writebol waited in a Liberian hospital, someone from the National Institutes of Health reached out to Samaritan's Purse, one of the two North Carolina-based Christian relief groups the two were working with, and offered to have vials of an experimental drug called ZMapp sent to Liberia, according to CNN's unnamed source. Although the Food and Drug Administration does allow experimental drugs to occasionally be distributed in life-threatening circumstances without approval under the expanded access or "compassionate use" conditions. It's not yet clear whether that approval was granted in this case or not. ... Brantly, who had been sick for nine days already ... [received] the first dose ... within an hour, he was able to breathe better and a rash on his body started to fade. The next day he was able to shower without help before boarding the air ambulance that flew him to Atlanta.