Dr. Kent Brantly and Nancy Writebol were flown separately from Liberia to Atlanta's Emory University Hospital -- the first human patients with Ebola to ever come to the United States.
Writebol was released from the hospital Tuesday. On Thursday morning, Brantly walked out of that same hospital with no signs of the virus in his system, doctors say.
Their recoveries seem to offer hope for those fighting the largest Ebola outbreak in known history. More than 2,400 people have been infected by the virus, according to the World Health Organization, and it's killed more than half.
But ZMapp is not an approved treatment for Ebola; in fact, no approved, proven treatment exists. So governments, aid organizations and scientists around the globe are racing to find a way to stop the virus.
Here are answers to questions about Ebola patients and treatments for the disease.
1. Are Brantly and Writebol cured?
Mostly. For Ebola patients to leave isolation, two blood tests had to come back negative for the Ebola virus. So their bodily fluids, like blood, sweat and feces, are no longer infectious.
"Nancy is free of the virus, but the lingering effects of the battle have left her in a significantly weakened condition," Writebol's husband, David Writebol, said in a statement.
Some doctors believe the virus can remain in vagin.al fluid and se.men for up to several months, according to WHO. Dr. Bruce Ribner, an infectious disease specialist at Emory, said there is no evidence Ebola has ever been transmitted this way, but the risk was discussed with both patients.
2. Are they now immune to Ebola?
Doctors believe surviving Ebola leaves you immune to future infection. Scientists have found that people who survive Ebola have antibodies in their blood that would provide protection against that strain of the virus in the future, and possibly against other strains as well.
But, as you can imagine, they haven't tested this theory by infecting survivors with the virus again.
There are four Ebola strains known to infect humans; the Zaire ebolavirus causing the current outbreak is the most common.
SEE full article at edition.cnn.com/2014/08/21/health/ebola-treatment-drug/index.html?hpt=iaf_c1