Experimental drug likely saved Ebola patientsBy Dr. Sanjay Gupta and Danielle Dellorto, CNNUpdated 8:22 PM ET, Tue August 5, 2014Just WatchedSecret serum likely saved Ebola patientsreplayMore Videos ...Secret serum likely saved Ebola patients 03:13Story highlightsUntested drugs can't be used in the midst of an outbreak, spokesman saysEbola drug ZMapp given to Dr. Kent Brantly and Nancy Writebol Experimental drug had only been tested in monkeys On Thursday, Dr. Kent Brantly thought he was going to die.It was the ninth day since the American missionary worker came down sick with Ebola in Liberia.His condition worsening by the minute, Brantly called his wife to say goodbye.Thankfully, the call was premature.Brantly is back on his feet -- literally -- after receiving a last-ditch, highly experimental drug. Another American missionary with Ebola got the same.Just WatchedTreatment for Ebola patientsreplayMore Videos ...Treatment for Ebola patients 02:51PLAY VIDEOJust WatchedWorld Bank commits to fighting EbolareplayMore Videos ...World Bank commits to fighting Ebola 01:27PLAY VIDEOJust WatchedTimeline of Ebola patient's U.S. returnreplayMore Videos ...Timeline of Ebola patient's U.S. return 02:11PLAY VIDEOPhotos: The Ebola epidemic 47 photosPhotos: The Ebola epidemic 47 photosThe Ebola epidemic – Red Cross workers, wearing protective suits, carry the body of a person who died from Ebola during a burial in Monrovia, Liberia, on Monday, January 5. Since the epidemic started a little more than a year ago in a remote village in Guinea, the world has seen more than 8,400 deaths, according to the latest numbers from the World Health Organization. And that number is believed to be low, since there was widespread under-reporting of cases, according to WHO.Hide Caption 1 of 47Photos: The Ebola epidemic 47 photosPauline Cafferkey, a Scottish woman diagnosed with Ebola, is put on a plane in Glasgow, Scotland, on Tuesday, December 30. Cafferkey, a 39-year-old nurse who volunteered in Sierra Leone, was being transported to London for treatment.Hide Caption 2 of 47Photos: The Ebola epidemic 47 photosLiberian President Ellen Johnson Sirleaf has her temperature taken before the opening of a new Ebola clinic Tuesday, November 25, in Monrovia.Hide Caption 3 of 47Photos: The Ebola epidemic 47 photosA child who survived the Ebola virus is fed by another survivor at a treatment center on the outskirts of Freetown, Sierra Leone, on Tuesday, November 11.Hide Caption 4 of 47Photos: The Ebola epidemic 47 photosHealth workers in Monrovia cover the body of a man suspected of dying from the Ebola virus on Friday, October 31.Hide Caption 5 of 47Photos: The Ebola epidemic 47 photosKaci Hickox leaves her home in Fort Kent, Maine, to take a bike ride with her boyfriend on Thursday, October 30. Hickox, a nurse, recently returned to the United States from West Africa, where she treated Ebola victims. State authorities wanted her to avoid public places for 21 days -- the virus' incubation period. But Hickox, who twice tested negative for Ebola, said she would defy efforts to keep her quarantined at home.Hide Caption 6 of 47Photos: The Ebola epidemic 47 photosCrew members at an airport in Accra, Ghana, unload supplies sent from China on Wednesday, October 29.Hide Caption 7 of 47Photos: The Ebola epidemic 47 photosHealth officials in Nairobi, Kenya, prepare to screen passengers arriving at the Jomo Kenyatta International Airport on Tuesday, October 28.Hide Caption 8 of 47Photos: The Ebola epidemic 47 photosU.S. President Barack Obama hugs Ebola survivor Nina Pham in the Oval Office of the White House on Friday, October 24. Pham, one of two Dallas nurses diagnosed with the virus, was declared Ebola-free after being treated at a hospital in Bethesda, Maryland. The other nurse, Amber Vinson (not pictured), was treated in Atlanta and also declared Ebola-free.Hide Caption 9 of 47Photos: The Ebola epidemic 47 photosHealth workers in Port Loko, Sierra Leone, transport the body of a person who is suspected to have died of Ebola on Tuesday, October 21.Hide Caption 10 of 47Photos: The Ebola epidemic 47 photosHealth workers bury a body on the outskirts of Monrovia on Monday, October 20.Hide Caption 11 of 47Photos: The Ebola epidemic 47 photosGarteh Korkoryah, center, is comforted during a memorial service for her son, Thomas Eric Duncan, on Saturday, October 18, in Salisbury, North Carolina. Duncan, a 42-year-old Liberian citizen, died October 8 in a Dallas hospital. He was in the country to visit his son and his son's mother, and he was the first person in the United States to be diagnosed with Ebola.Hide Caption 12 of 47Photos: The Ebola epidemic 47 photosBoys run from blowing dust as a U.S. military aircraft leaves the construction site of an Ebola treatment center in Tubmanburg, Liberia, on Wednesday, October 15.Hide Caption 13 of 47Photos: The Ebola epidemic 47 photosAid workers from the Liberian Medical Renaissance League stage an Ebola awareness event October 15 in Monrovia. The group performs street dramas throughout Monrovia to educate the public on Ebola symptoms and how to handle people who are infected with the virus.Hide Caption 14 of 47Photos: The Ebola epidemic 47 photosEbola survivors prepare to leave a Doctors Without Borders treatment center after recovering from the virus in Paynesville, Liberia, on October 12.Hide Caption 15 of 47Photos: The Ebola epidemic 47 photosA woman crawls toward the body of her sister as a burial team takes her away for cremation Friday, October 10, in Monrovia. The sister had died from Ebola earlier in the morning while trying to walk to a treatment center, according to her relatives.Hide Caption 16 of 47Photos: The Ebola epidemic 47 photosA person peeks out from the Dallas apartment where Thomas Eric Duncan, the first person diagnosed with the Ebola virus in the United States, was staying on Friday, October 3.Hide Caption 17 of 47Photos: The Ebola epidemic 47 photosA girl cries as community activists approach her outside her Monrovia home on Thursday, October 2, a day after her mother was taken to an Ebola ward.Hide Caption 18 of 47Photos: The Ebola epidemic 47 photosA health official uses a thermometer Monday, September 29, to screen a Ukrainian crew member on the deck of a cargo ship at the Apapa port in Lagos, Nigeria.Hide Caption 19 of 47Photos: The Ebola epidemic 47 photosWorkers move a building into place as part of a new Ebola treatment center in Monrovia on September 28.Hide Caption 20 of 47Photos: The Ebola epidemic 47 photosMedical staff members at the Doctors Without Borders facility in Monrovia burn clothes belonging to Ebola patients on Saturday, September 27. Hide Caption 21 of 47Photos: The Ebola epidemic 47 photosMedics load an Ebola patient onto a plane at Sierra Leone's Freetown-Lungi International Airport on Monday, September 22.Hide Caption 22 of 47Photos: The Ebola epidemic 47 photosA few people are seen in Freetown during a three-day nationwide lockdown on Sunday, September 21. In an attempt to curb the spread of the Ebola virus, people in Sierra Leone were told to stay in their homes.Hide Caption 23 of 47Photos: The Ebola epidemic 47 photosSupplies wait to be loaded onto an aircraft at New York's John F. Kennedy International Airport on Saturday, September 20. It was the largest single shipment of aid to the Ebola zone to date, and it was coordinated by the Clinton Global Initiative and other U.S. aid organizations.Hide Caption 24 of 47Photos: The Ebola epidemic 47 photosA child stops on a Monrovia street Friday, September 12, to look at a man who is suspected of suffering from Ebola.Hide Caption 25 of 47Photos: The Ebola epidemic 47 photosHealth workers in Monrovia place a corpse into a body bag on Thursday, September 4.Hide Caption 26 of 47Photos: The Ebola epidemic 47 photosAfter an Ebola case was confirmed in Senegal, people load cars with household items as they prepare to cross into Guinea from the border town of Diaobe, Senegal, on Wednesday, September 3.Hide Caption 27 of 47Photos: The Ebola epidemic 47 photosCrowds cheer and celebrate in the streets Saturday, August 30, after Liberian authorities reopened the West Point slum in Monrovia. The military had been enforcing a quarantine on West Point, fearing a spread of the Ebola virus.Hide Caption 28 of 47Photos: The Ebola epidemic 47 photosA health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia on Friday, August 29. Hide Caption 29 of 47Photos: The Ebola epidemic 47 photosVolunteers working with the bodies of Ebola victims in Kenema, Sierra Leone, sterilize their uniforms on Sunday, August 24. Hide Caption 30 of 47Photos: The Ebola epidemic 47 photosA burial team from the Liberian Ministry of Health unloads bodies of Ebola victims onto a funeral pyre at a crematorium in Marshall, Liberia, on Friday, August 22.Hide Caption 31 of 47Photos: The Ebola epidemic 47 photosDr. Kent Brantly leaves Emory University Hospital on Thursday, August 21, after being declared no longer infectious from the Ebola virus. Brantly was one of two American missionaries brought to Emory for treatment of the deadly virus.Hide Caption 32 of 47Photos: The Ebola epidemic 47 photosAn Ebola Task Force soldier beats a local resident while enforcing a quarantine on the West Point slum on August 20.Hide Caption 33 of 47Photos: The Ebola epidemic 47 photosLocal residents gather around a very sick Saah Exco, 10, in a back alley of the West Point slum on Tuesday, August 19. The boy was one of the patients that was pulled out of a holding center for suspected Ebola patients after the facility was overrun and closed by a mob on August 16. A local clinic then refused to treat Saah, according to residents, because of the danger of infection. Although he was never tested for Ebola, Saah's mother and brother died in the holding center.Hide Caption 34 of 47Photos: The Ebola epidemic 47 photosA burial team wearing protective clothing retrieves the body of a 60-year-old Ebola victim from his home near Monrovia on Sunday, August 17. Hide Caption 35 of 47Photos: The Ebola epidemic 47 photosWorkers prepare the new Ebola treatment center on August 17.Hide Caption 36 of 47Photos: The Ebola epidemic 47 photosLiberian police depart after firing shots in the air while trying to protect an Ebola burial team in the West Point slum of Monrovia on August 16. A crowd of several hundred local residents reportedly drove away the burial team and their police escort. The mob then forced open an Ebola isolation ward and took patients out, saying the Ebola epidemic is a hoax.Hide Caption 37 of 47Photos: The Ebola epidemic 47 photosA crowd enters the grounds of an Ebola isolation center in the West Point slum on August 16. The mob was reportedly shouting, "No Ebola in West Point."Hide Caption 38 of 47Photos: The Ebola epidemic 47 photosA health worker disinfects a corpse after a man died in a classroom being used as an Ebola isolation ward Friday, August 15, in Monrovia.Hide Caption 39 of 47Photos: The Ebola epidemic 47 photosHealth workers in Kenema screen people for the Ebola virus on Saturday, August 9, before they enter the Kenema Government Hospital.Hide Caption 40 of 47Photos: The Ebola epidemic 47 photosAid worker Nancy Writebol, wearing a protective suit, gets wheeled on a gurney into Emory University Hospital in Atlanta on August 5. A medical plane flew Writebol from Liberia to the United States after she and her colleague Dr. Kent Brantly were infected with the Ebola virus in the West African country. Hide Caption 41 of 47Photos: The Ebola epidemic 47 photosMembers of Doctors Without Borders adjust tents in the isolation area in Kailahun on July 20.Hide Caption 42 of 47Photos: The Ebola epidemic 47 photosBoots dry in the Ebola treatment center in Kailahun on July 20.Hide Caption 43 of 47Photos: The Ebola epidemic 47 photosDr. Jose Rovira of the World Health Organization takes a swab from a suspected Ebola victim in Pendembu, Sierra Leone, on Friday, July 18.Hide Caption 44 of 47Photos: The Ebola epidemic 47 photosRed Cross volunteers disinfect each other with chlorine after removing the body of an Ebola victim from a house in Pendembu on July 18.Hide Caption 45 of 47Photos: The Ebola epidemic 47 photosA scientist separates blood cells from plasma cells to isolate any Ebola RNA and test for the virus Thursday, April 3, at the European Mobile Laboratory in Gueckedou, Guinea.Hide Caption 46 of 47Photos: The Ebola epidemic 47 photosHealth specialists work Monday, March 31, at an isolation ward for patients at the facility in southern Guinea.Hide Caption 47 of 47EXPAND GALLERYBrantly's and Nancy Writebol's conditions significantly improved after receiving the medication, sources say. Brantly was able to walk into Emory University Hospital in Atlanta after being evacuated to the United States last week, and Writebol is expected to arrive in Atlanta on Tuesday. On July 22, Brantly woke up feeling feverish. Fearing the worst, Brantly immediately isolated himself. Writebol's symptoms started three days later. A rapid field blood test confirmed the infection in both of them after they had become ill with fever, vomiting and diarrhea.It's believed Brantly and Writebol, who worked with the aid organization Samaritan's Purse, contracted Ebola from another health care worker at their hospital in Liberia, although the official Centers for Disease Control and Prevention case investigation has yet to be released.The experimental drug, known as ZMapp, was developed by the biotech firm Mapp Biopharmaceutical Inc., which is based in San Diego. The patients were told that the treatment had never been tried before in a human being but had shown promise in small experiments with monkeys. Questions about this new Ebola drugJust WatchedHow the experimental Ebola serum works replayMore Videos ...How the experimental Ebola serum works 02:32PLAY VIDEOAccording to company documents, four monkeys infected with Ebola survived after being given the therapy within 24 hours after infection. Two of four other monkeys that started therapy within 48 hours after infection also survived. One monkey that was not treated died within five days of exposure to the virus.Brantly and Writebol were aware of the risk of taking a new, little-understood treatment and gave informed consent, according to two sources familiar with the care of the missionary workers. In the monkeys, the experimental serum had been given within 48 hours of infection. Brantly didn't receive it until he'd been sick for nine days.The medicine is a three-mouse monoclonal antibody, meaning that mice were exposed to fragments of the Ebola virus and then the antibodies generated within the mice's blood were harvested to create the medicine. It works by preventing the virus from entering and infecting new cells.The Ebola virus causes viral hemorrhagic fever, which refers to a group of viruses that affect multiple organ systems in the body and are often accompanied by bleeding.Early symptoms include sudden onset of fever, weakness, muscle pain, headaches and a sore throat. They later progress to vomiting, diarrhea, impaired kidney and liver function -- and sometimes internal and external bleeding.Map: The Ebola outbreakEXPAND IMAGEThe ZMapp vials, stored at subzero temperatures, reached the hospital in Liberia where Brantly and Writebol were being treated Thursday morning. Doctors were instructed to allow the serum to thaw naturally without any additional heat. It was expected that it would be eight to 10 hours before the medicine could be given, according to a source familiar with the process. Brantly asked that Writebol be given the first dose because he was younger and he thought he had a better chance of fighting it, and she agreed. However, as the first vial was still thawing, Brantly's condition took a sudden turn for the worse.Brantly began to deteriorate and developed labored breathing. He told his doctors he thought he was dying, according to a source with firsthand knowledge of the situation. Knowing his dose was still frozen, Brantly asked if he could have Writebol's now-thawed medication. It was brought to his room and administered through an IV. Within an hour of receiving the medication, Brantly's condition dramatically improved. He began breathing easier; the rash over his trunk faded away. One of his doctors described the events as "miraculous." By the next morning, Brantly was able to take a shower on his own before getting on a specially designed Gulfstream air ambulance jet to be evacuated to the United States.Writebol also received a vial of the medication. Her response was not as remarkable, according to sources familiar with the treatment. However, doctors on Sunday administered Writebol a second dose of the medication, which resulted in significant improvement. Just WatchedWhy isn't there an Ebola vaccine?replayMore Videos ...Why isn't there an Ebola vaccine? 02:31PLAY VIDEOJust WatchedSecond Ebola patient heading to U.S.replayMore Videos ...Second Ebola patient heading to U.S. 01:57PLAY VIDEOJust WatchedDoctors struggle to treat Ebola patientsreplayMore Videos ...Doctors struggle to treat Ebola patients 04:37PLAY VIDEOShe was stable enough to be evacuated back to the United States.The process by which the medication was made available to Brantly and Writebol is highly unusual.World Health Organization spokesman Gregory Hartl cautioned that health authorities "cannot start using untested drugs in the middle of an outbreak, for various reasons."Doctors Without Borders similarly weighed in on the side of caution."It is important to keep in mind that a large-scale provision of treatments and vaccines that are in very early stages of development has a series of scientific and ethical implications," the organization said in a statement."As doctors, trying an untested drug on patients is a very difficult choice since our first priority is to do no harm, and we would not be sure that the experimental treatment would do more harm than good."ZMapp has not been approved for human use and has not even gone through the clinical trial process, which is standard to prove the safety and efficacy of a medication. It may have been given under the U.S. Food and Drug Administration's "compassionate use" regulation, which allows access to investigational drugs outside clinical trials. Getting approval for compassionate use is often long and laborious, but in the case of Brantly and Writebol, they received the medication within seven to 10 days of their exposure to the Ebola virus.On July 30, the Defense Threat Reduction Agency, an arm of the military responsible for any chemical, biological, radiological, nuclear and high-yield explosive threats, allotted additional funding to MAPP Biopharmaceutical due to "promising results."American Ebola patient 'seems to be improving'Ebola outbreakHow the world reacted as Ebola spreadThe largest Ebola epidemic in history began with the simple act of caring for a child. Soon, it spread from the remote village in Guinea.Countries with travel restrictionsThe worst-ever outbreak of Ebola virus is stretching the medical capacities of Guinea, Liberia and Sierra Leone.Who is patient zero?Before the deaths soared into the thousands, before the outbreak triggered global fears, Ebola struck a toddler named Emile Ouamouno. The messy truth about EbolaWhat happens when you get Ebola? CNN's Miguel Marquez explains.Millions of vaccines planned by 2015 Health experts are fast-tracking tests for various vaccines, and hope to have millions of experimental doses by next year.How the Ebola virus spreadsEbola is a scary infectious disease but the first thing you should know is that it's not very contagious. Here is how it spreads.What you need to knowThese questions and answers will give you the latest information on the deadly virus and what's being done to stop its spread.3 with Ebola will fly each monthUp to three Ebola-infected travelers might board an international flight each month in West Africa, according to a new study, and potentially spread the deadly virus.Why some survive, some don'tThere's no cure for Ebola. So why have some patients walked away healthy while others in the West died? Inside the world's worst outbreakA doctor at a government-run Ebola treatment center in Monrovia is too busy to mince words.Stigmatized, abandoned orphansTwo children orphaned by Ebola play in the empty corner of a Liberian orphanage. Their parents died last month, and none of the extended family is willing to claim them. Five ways the CDC got it wrongPublic health experts are asking whether the CDC is partly to blame for problems with Ebola in the U.S. Here are 5 things they say the CDC is getting wrong.Can pets get or spread Ebola? The lack of solid protocol on what to do with Ebola victims' pets and what little is known about the risk has caused one dog to be euthanized and another quarantined. A look at Ebola protective gearRosie Tomkins takes a look at the protective suits that are worn by some Ebola medical workers in Africa.How hospitals handle Ebola patientsWhat's the protocol for health care workers if they suspect a patient has the virusEbola outbreak in West AfricaClick through our gallery as we track the Ebola outbreak in West Africa. Complete coverage on EbolaA look at CNN's complete coverage on the Ebola crisis. 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How the world reacted as Ebola spreadThe largest Ebola epidemic in history began with the simple act of caring for a child. Soon, it spread from the remote village in Guinea.
Countries with travel restrictionsThe worst-ever outbreak of Ebola virus is stretching the medical capacities of Guinea, Liberia and Sierra Leone.
Who is patient zero?Before the deaths soared into the thousands, before the outbreak triggered global fears, Ebola struck a toddler named Emile Ouamouno.
Millions of vaccines planned by 2015 Health experts are fast-tracking tests for various vaccines, and hope to have millions of experimental doses by next year.
How the Ebola virus spreadsEbola is a scary infectious disease but the first thing you should know is that it's not very contagious. Here is how it spreads.
What you need to knowThese questions and answers will give you the latest information on the deadly virus and what's being done to stop its spread.
3 with Ebola will fly each monthUp to three Ebola-infected travelers might board an international flight each month in West Africa, according to a new study, and potentially spread the deadly virus.
Why some survive, some don'tThere's no cure for Ebola. So why have some patients walked away healthy while others in the West died?
Inside the world's worst outbreakA doctor at a government-run Ebola treatment center in Monrovia is too busy to mince words.
Stigmatized, abandoned orphansTwo children orphaned by Ebola play in the empty corner of a Liberian orphanage. Their parents died last month, and none of the extended family is willing to claim them.
Five ways the CDC got it wrongPublic health experts are asking whether the CDC is partly to blame for problems with Ebola in the U.S. Here are 5 things they say the CDC is getting wrong.
Can pets get or spread Ebola? The lack of solid protocol on what to do with Ebola victims' pets and what little is known about the risk has caused one dog to be euthanized and another quarantined.
A look at Ebola protective gearRosie Tomkins takes a look at the protective suits that are worn by some Ebola medical workers in Africa.
How hospitals handle Ebola patientsWhat's the protocol for health care workers if they suspect a patient has the virus
Ebola outbreak in West AfricaClick through our gallery as we track the Ebola outbreak in West Africa.