Supportive care may help American Ebola patients survive

Nurse Amber Vinson's discharge from the hospital Tuesday brings to seven the number of American patients who have survived Ebola, leading many people to wonder what has allowed them to beat the odds.

In West Africa, about 70% of patients die from the Ebola virus, according to the World Health Organization.

Vinson, 29, was released Tuesday from Atlanta's Emory University Hospital. She was infected with Ebola while working at Texas Health Presbyterian Hospital in Dallas, where she was part of the care team for Thomas Eric Duncan, a Liberian national who was the first person to be diagnosed with Ebola in the USA. Duncan died Oct. 8.

As she was released, Vinson thanked Ebola survivors Kent Brantly and Nancy Writebol for donating blood to help her. Vinson ended up receiving blood only from Brantly, who also donated blood to several other surviving patients. Doctors have been experimenting with blood transfusions in the hope that a survivor's blood will contain antibodies to help other patients fight the virus.

Vinson's fellow nurse, 26-year-old Nina Pham, who also contracted Ebola while treating Duncan, was released from the National Institutes of Health last week. Pham also received blood from Brantly.

American Ebola survivors now include Brantly, a doctor who worked for the aid group Samaritan's Purse; Writebol, who worked as a missionary for SIM USA; physician Richard Sacra, who also worked for SIM USA; cameraman Ashoka Mukpo; an anonymous patient.

A handful of Ebola patients evacuated to Europe also have survived, but two Spanish priests infected with the virus in West Africa died.

In some ways, it's easy to see why Westerners have done so well.

All of the survivors have gotten state-of-the-art care at hospitals with specialized biocontainment units designed to handle the most dangerous infectious diseases.

In West Africa, many patients never make it to the hospital. Hospitals have beds for only one in five Ebola patients in Liberia, according to the WHO. Doctors at Ebola treatment centers in Africa often lack personal protective equipment such as gloves and gowns, or even running water and soap.

At least 450 health care workers have been infected with Ebola in West Africa and 244 have died. Overall, more than 10,000 people have been infected and nearly 5,000 have died, according to the WHO.

Studies of African patients have shown that ones who are in better condition at the time of infection — with better nutrition and overall health — are more likely to survive Ebola. Younger people and those who receive blood transfusions also fare better, said Peter Hotez, dean of the National School of Tropical Medicine in at Baylor College of Medicine in Houston.

Emory treated four of the survivors — Vinson, Brantly, Writebol and the unidentified patient. The Nebraska Medical Center in Omaha treated Sacra and Mukpo.

Those hospitals have excellent intensive care units, where doctors could prevent some of the most dangerous complications of Ebola, such as dehydration and electrolyte imbalances, which can cause heart rhythm disturbances, said Robert Murphy, director of the Center for Global Health at Northwestern University in Chicago. American hospitals also have a variety of ways to maintain stable blood pressure, control pain and treat bacterial infections.

Vinson's physician, Bruce Ribner, said he has learned that it's possible to treat Ebola patients much more aggressively than doctors once believed, using ventilators to help them breathe and kidney dialysis if their kidneys begin to fail.

In an address to an infectious disease conference earlier this month, Ribner mentioned that Ebola patients lose an extraordinary amount of fluid — 5 to 10 liters a day — because of heavy vomiting and diarrhea.

But Ribner said it's impossible to know exactly where to give credit or why the nurses recovered relatively quickly.

Both nurses were hospitalized only two weeks. Other Ebola survivors had a much longer course of illness. An anonymous patient treated at Emory, for example, was hospitalized for six weeks.

Still, there's no way to know how these people would have done if given other types of treatment, Hotez said.

"The honest answer is that we're not exactly sure" why the nurses recovered so quickly, said Ribner, medical director of Emory's Serious Communicable Disease Unit. But he said that the nurses' age and circumstances of how they contracted Ebola may help explain their relatively rapid recovery.

"They are two of the youngest patients treated in developed countries," Ribner said. "We know from a lot of data that younger patients do much better than patients who are older."

In addition, Ribner noted that Vinson and Pham may have been infected with a smaller quantity of virus, because their personal protective equipment covered most of their bodies. A small amount of virus is generally easier to fight off, he said.

"It is quite likely that the amount of virus that she was exposed to was substantially less than in patients who get infected in Africa," Ribner said. "The higher the load you get infected with, the more serious your disease is likely to be."

Hotez said that the American survivors may have benefited from early intervention. Brantly, Writebol and Sacra were sick for several days before leaving Liberia, for example, but both nurses were treated as soon as they developed fevers. In Liberia, patients lucky enough to reach the hospital have typically been sick for five days.

Hotez said Americans probably benefited from experimental drugs and transfusions from Ebola survivors, although it's not possible to say for sure. Pham, Sacra and Mukpo all received donated plasma — the liquid part of the blood that contains antibodies — from Brantly, who himself got a transfusion from a survivor before leaving Africa.

Physician Craig Spencer, who contracted Ebola while working for Doctors Without Borders and is hospitalized in New York, received a blood transfusion from Writebol.

Although Duncan didn't receive a blood donation — the Dallas hospital has said his blood type didn't match — he did receive an experimental drug called brincidofovir a few days before he died. Mukpo received the same drug. Sacra received an experimental drug called TKM-Ebola. Brantly and Writebol got an experimental drug called ZMapp.

"Mr. Duncan had an unfortunate delay in diagnosis and did not receive an experimental therapy until just before he died," Murphy said. "That did not help his case."

"It's important to administer these interventions early in the course of the illness before the viral load starts to rise exponentially later in the course of the illness," Hotez said. "It's possible that the one death we have seen in the United States was because that individual may not have received intervention soon enough."