Story highlights U.S. reaches contract for development of experimental ZMapp drug

FDA gives green light for Ebola vaccine human safety trial to begin

This will be the first test of this type of Ebola vaccine in humans

Vaccine will be given to 20 healthy volunteers at the NIH in Maryland

A highly anticipated test of an experimental Ebola vaccine will begin this week at the National Institutes of Health, amid mounting anxiety about the spread of the deadly virus in West Africa.

After an expedited review by the U.S. Food and Drug Administration, researchers were given the green light to begin what's called a human safety trial, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID).

It will be the first test of this type of Ebola vaccine in humans.

The experimental vaccine, developed by the pharmaceutical company GlaxoSmithKline and the NIAID, will first be given to three healthy human volunteers to see if they suffer any adverse effects. If deemed safe, it will then be given to another small group of volunteers, aged 18 to 50, to see if it produces a strong immune response to the virus. All will be monitored closely for side effects.

The vaccine will be administered to volunteers by an injection in the deltoid muscle of their arm, first in a lower dose, then later in a higher dose after the safety of the vaccine has been determined.

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Photos: The Ebola epidemic Photos: The Ebola epidemic An Ebola survivor participates in a study in Monrovia, Liberia, on June 17, 2015. The country launched a five-year study to unravel the mystery of the long-term health effects that plague survivors of the viral disease. Since the epidemic started more than a year ago in a remote village in Guinea, more than 11,000 people have died, the vast majority in three West African nations, 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 45 Photos: The Ebola epidemic Women in Monrovia celebrate after the World Health Organization declared Liberia Ebola-free on May 9, 2015. Other cases have recurred since, however. Two people in Liberia have died of the disease since the end of June, just weeks after the WHO declared the nation free of the disease. Hide Caption 2 of 45 Photos: The Ebola epidemic A man walks past an Ebola awareness painting in Monrovia on March 22, 2015. Hide Caption 3 of 45 Photos: The Ebola epidemic Soldiers from the U.S. Army's 101st Airborne Division walk across the tarmac at Campbell Army Airfield before reuniting with their families at a homecoming ceremony March 21, 2015 in Fort Campbell, Kentucky. The 162 soldiers were deployed in Liberia, where they helped fight the spread of Ebola. Hide Caption 4 of 45 Photos: The Ebola epidemic Relatives weep for a loved one who it was believed died from Ebola, at a graveyard on the outskirts of Monrovia on March 11, 2015. Hide Caption 5 of 45 Photos: The Ebola epidemic Doctors Without Borders staffer Alex Eilert Paulsen watches as mattresses and bed frames burn at the Ebola Treatment Unit in Paynesville, Liberia, on January 31, 2015. The organization reduced its number of beds from 250 to 30 as gains were made in battling the virus. Hide Caption 6 of 45 Photos: The Ebola epidemic Pauline Cafferkey, a Scottish woman diagnosed with Ebola, is put on a plane in Glasgow, Scotland, on December 30, 2014. Cafferkey, a 39-year-old nurse who volunteered in Sierra Leone, was being transported to London for treatment. Hide Caption 7 of 45 Photos: The Ebola epidemic A child who survived the Ebola virus is fed by another survivor at a treatment center on the outskirts of Freetown, Sierra Leone, on November 11, 2014. Hide Caption 8 of 45 Photos: The Ebola epidemic Health workers in Monrovia cover the body of a man suspected of dying from the Ebola virus on October 31, 2014. Hide Caption 9 of 45 Photos: The Ebola epidemic Kaci Hickox leaves her home in Fort Kent, Maine, to take a bike ride with her boyfriend on October 30, 2014. 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 10 of 45 Photos: The Ebola epidemic Health officials in Nairobi, Kenya, prepare to screen passengers arriving at the Jomo Kenyatta International Airport on October 28, 2014. Hide Caption 11 of 45 Photos: The Ebola epidemic U.S. President Barack Obama hugs Ebola survivor Nina Pham in the Oval Office of the White House on October 24, 2014. 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 12 of 45 Photos: The Ebola epidemic Health workers in Port Loko, Sierra Leone, transport the body of a person who is suspected to have died of Ebola on October 21, 2014. Hide Caption 13 of 45 Photos: The Ebola epidemic Health workers bury a body on the outskirts of Monrovia on October 20, 2014. Hide Caption 14 of 45 Photos: The Ebola epidemic Garteh Korkoryah, center, is comforted during a memorial service for her son, Thomas Eric Duncan, on October 18, 2014, 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 15 of 45 Photos: The Ebola epidemic Boys run from blowing dust as a U.S. military aircraft leaves the construction site of an Ebola treatment center in Tubmanburg, Liberia, on October 15, 2014. Hide Caption 16 of 45 Photos: The Ebola epidemic Aid workers from the Liberian Medical Renaissance League stage an Ebola awareness event October 15, 2014, 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 17 of 45 Photos: The Ebola epidemic Ebola survivors prepare to leave a Doctors Without Borders treatment center after recovering from the virus in Paynesville, Liberia, on October 12, 2014. Hide Caption 18 of 45 Photos: The Ebola epidemic A man dressed in protective clothing treats the front porch of a Dallas apartment on October 12, 2014. The apartment is home to one of the two nurses who were diagnosed with Ebola after treating Thomas Eric Duncan, a Liberian national who traveled to Dallas and later died from the virus. Hide Caption 19 of 45 Photos: The Ebola epidemic A woman crawls toward the body of her sister as a burial team takes her away for cremation October 10, 2014, 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 20 of 45 Photos: The Ebola epidemic A man digs a grave on October 7, 2014, outside an Ebola treatment center near Gbarnga, Liberia. Hide Caption 21 of 45 Photos: The Ebola epidemic A 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 October 3, 2014. Hide Caption 22 of 45 Photos: The Ebola epidemic A girl cries as community activists approach her outside her Monrovia home on October 2, 2014, a day after her mother was taken to an Ebola ward. Hide Caption 23 of 45 Photos: The Ebola epidemic A health official uses a thermometer September 29, 2014, to screen a Ukrainian crew member on the deck of a cargo ship at the Apapa port in Lagos, Nigeria. Hide Caption 24 of 45 Photos: The Ebola epidemic Workers move a building into place as part of a new Ebola treatment center in Monrovia on September 28, 2014. Hide Caption 25 of 45 Photos: The Ebola epidemic Medics load an Ebola patient onto a plane at Sierra Leone's Freetown-Lungi International Airport on September 22, 2014. Hide Caption 26 of 45 Photos: The Ebola epidemic A few people are seen in Freetown during a three-day nationwide lockdown on September 21, 2014. In an attempt to curb the spread of the Ebola virus, people in Sierra Leone were told to stay in their homes. Hide Caption 27 of 45 Photos: The Ebola epidemic Supplies wait to be loaded onto an aircraft at New York's John F. Kennedy International Airport on September 20, 2014. 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 28 of 45 Photos: The Ebola epidemic A child stops on a Monrovia street September 12, 2014, to look at a man who is suspected of suffering from Ebola. Hide Caption 29 of 45 Photos: The Ebola epidemic After 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 September 3, 2014. Hide Caption 30 of 45 Photos: The Ebola epidemic A health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia on August 29, 2014. Hide Caption 31 of 45 Photos: The Ebola epidemic A burial team from the Liberian Ministry of Health unloads bodies of Ebola victims onto a funeral pyre at a crematorium in Marshall, Liberia, on August 22, 2014. Hide Caption 32 of 45 Photos: The Ebola epidemic Dr. Kent Brantly leaves Emory University Hospital on August 21, 2014, 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 33 of 45 Photos: The Ebola epidemic An Ebola Task Force soldier beats a local resident while enforcing a quarantine on the West Point slum on August 20, 2014. Hide Caption 34 of 45 Photos: The Ebola epidemic Local residents gather around a very sick Saah Exco, 10, in a back alley of the West Point slum on August 19, 2014. 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 35 of 45 Photos: The Ebola epidemic Workers prepare the new Ebola treatment center on August 17, 2014. Hide Caption 36 of 45 Photos: The Ebola epidemic Liberian 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, 2014. 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 45 Photos: The Ebola epidemic A health worker disinfects a corpse after a man died in a classroom being used as an Ebola isolation ward August 15, 2014, in Monrovia. Hide Caption 38 of 45 Photos: The Ebola epidemic Aid worker Nancy Writebol, wearing a protective suit, gets wheeled on a gurney into Emory University Hospital in Atlanta on August 5, 2014. 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 39 of 45 Photos: The Ebola epidemic Members of Doctors Without Borders adjust tents in the isolation area in Kailahun on July 20, 2014. Hide Caption 40 of 45 Photos: The Ebola epidemic Boots dry in the Ebola treatment center in Kailahun on July 20, 2014. Hide Caption 41 of 45 Photos: The Ebola epidemic Dr. Jose Rovira of the World Health Organization takes a swab from a suspected Ebola victim in Pendembu, Sierra Leone, on July 18, 2014. Hide Caption 42 of 45 Photos: The Ebola epidemic Red Cross volunteers disinfect each other with chlorine after removing the body of an Ebola victim from a house in Pendembu on July 18, 2014. Hide Caption 43 of 45 Photos: The Ebola epidemic A scientist separates blood cells from plasma cells to isolate any Ebola RNA and test for the virus April 3, 2014, at the European Mobile Laboratory in Gueckedou, Guinea. Hide Caption 44 of 45 Photos: The Ebola epidemic Health specialists work March 31, 2014, at an isolation ward for patients at the facility in southern Guinea. Hide Caption 45 of 45

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Some of the preclinical studies that are normally done on these types of vaccines were waived by the FDA during the expedited review, Fauci said, so "we want to take extra special care that we go slowly with the dosing."

The vaccine did extremely well in earlier trials with chimpanzees, Fauci said. He noted that the method being used to prompt an immune response to Ebola cannot cause a healthy individual to become infected with the virus.

Still, he said, "I have been fooled enough in my many years of experience... you really can't predict what you will see (in humans)."

According to the NIH, the vaccine will also be tested on healthy volunteers in the United Kingdom, Gambia and Mali, once details are finalized with health officials in those countries.

Trials cannot currently be done in the four countries affected by the recent outbreak -- Guinea, Sierra Leone, Liberia and Nigeria -- because the existing health care infrastructure wouldn't support them, Fauci said. Gambia and Mali were selected because the NIH has "long-standing collaborative relationships" with researchers in those countries.

According to the NIH, officials from the Centers for Disease Control and Prevention are also in talks with health officials from Nigeria about conducting part of the safety trial there.

Funding from an international consortium formed to fight Ebola will enable GlaxoSmithKline to begin manufacturing up to 10,000 additional doses of the vaccine while clinical trials are ongoing, the pharmaceutical company said in a statement . These doses would be made available if the World Health Organization decides to allow emergency immunizations in high-risk communities.

The GSK/NIAID vaccine is one of two leading candidate vaccines. The other was developed by the Public Health Agency of Canada and licensed this month to NewLink Genetics, a company based in Iowa.

According to the NIH, safety trials of that vaccine will start this fall.

Earlier this month, the Canadian government shipped what it said was "800 to 1,000" doses of that vaccine to Liberia, at the government's request. It's not clear whether it has been given to health workers or anyone else there.

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Worth noting: In 2009, an earlier version of the vaccine was given to a lab worker in Germany after he thought he had pricked himself with a needle tainted with Ebola. He did not develop the disease.

While there currently is no proven treatment for Ebola beyond supportive care, government agencies and small biotech firms have been scrambling to speed up development of several potential therapies and vaccines.

A third vaccine, also developed by the NIH, was recently tested in primates and found to protect them from infection; it was given in combination with Depovax, an adjuvant that has been used with other vaccines and cancer therapies to boost the body's immune response.

While vaccines might be given to prevent infection among health workers or other people thought to be at high risk, development has also been sped up on drugs that might potentially be given to patients who already have the disease.

The drug that's received the most attention is ZMapp, which has been given to at least seven individuals in the current outbreak, including two American missionary medical workers, Nancy Writebol and Dr. Kent Brantly

The drug has never been formally tested in humans, and while the results in human patients are encouraging -- five of the seven known to have received it are still alive -- experts say there is too little data to say whether it played a role in their recoveries.

Earlier versions of ZMapp, which received backing from the U.S. and Canadian governments as well as from biotech firms, have shown some ability to protect rhesus macaque monkeys more than two days after they were infected with the virus.

The U.S. Department of Health and Human Services announced on Tuesday a $24.9 million, 18-month contract with ZMapp's manufacturer, Mapp Biopharmaceutical, to accelerate the development of the medication.

Mapp will make "a small amount of the drug for early stage clinical safety studies and nonclinical studies" to gauge how the drug works on people, the HHS department said in a news release. The various new steps "will contribute to increasing the amount of product potentially available to treat patients with Ebola."

Another drug, TKM-Ebola, has been tested for safety in a small number of humans. That trial was put on hold in January, after one volunteer developed moderate gastrointestinal side effects after receiving a high dose of the medication.

Last month, the FDA modified the hold to a "partial clinical hold." In effect, this means that Tekmira could potentially be allowed to give the drug to doctors or hospitals who request it, on an emergency basis. There's no indication that the company has received any such requests.

The vaccine going into trials this week is based on an adenovirus -- a type of cold virus -- that's found in chimpanzees. The virus delivers genetic material derived from two species of Ebola virus, including the Zaire strain that's responsible for the current outbreak. Those genes are meant to trigger the development of antibodies in the person who receives the vaccine, antibodies that can specifically defend against Ebola.

Another trial, using a version of the GSK/NIAID vaccine that uses only the Zaire strain of Ebola, will be launched in October, according to the NIH.

All participants in the trial will be evaluated nine times over a 48-week period. NIH expects to reveal the results of the trial by the end of the year.

If it's approved for widespread use, the first priority will be to give the vaccine to health care workers or lab workers who are fighting the spread of the virus, Fauci said. It will then be considered for people in the communities where outbreaks occur.