The two Americans infected with Ebola have seen some improvement after being administered an experimental treatment.
Kent Brantley and Nancy Writebol were both infected while trying to stem the outbreak in West Africa, working with the humanitarian organization Samaritan's Purse. (Via ABC)
Brantley received a dose of the experimental serum and within an hour his condition significantly improved.
Newscasts even showed him walking into Emory University Hospital in Atlanta after he was flown back to the U.S. for treatment. (Via WXIA)
Writebol received two doses of the serum and, although she hasn't shown as much improvement as Brantley, she did get well enough to allow doctors to transfer her to Emory Hospital as well. (Via WCNC)
So what's the story behind this experimental treatment?
The serum was developed by MAPP Biopharmaceutical and has not yet been approved for use by the FDA. It hasn't even undergone human testing, which makes Brantley and Writebol the first people to receive the drug.
The drug, called ZMapp, is one of the first treatments to show promise combatting Ebola and works by preventing the virus from entering and infecting new cells. (Via European Commission DG ECHO / CC BY-ND 2.0)
Normally, it would be illegal to administer an un-tested drug but CNN speculates this case falls under the FDA's "compassionate use" regulation which allows for drugs such as this one to be used outside clinical trials.
It's unclear how much of this serum exists right now. ABC reports that when the three doses were shipped to Liberia, doctors weren't even sure if there would be enough for the two patients.
However, the Defense Threat Reduction Agency announced it will increase funding for MAPP Biopharmaceutical to further develop the drug. (Via Global Biodefense)
There's currently no timetable for when the drug will be formally tested, so it's not clear when the serum will become more widely available or whether it could have an impact on the Ebola outbreak in West Africa that has killed at least 800 people so far.