Since transfusion is generally used as an emergency measure, there's almost no scientific research about its use, especially when it comes to Ebola. This means that even the WHO still has a lot of questions about it: "Who does it work on, how does it work exactly, when doesn't it work, what's the right amount to give, all those things—that information really isn't clear," says Harris.
The first and last time transfusions were used to treat Ebola was in 1995, during the most recent outbreak of the disease, in what is now the Democratic Republic of the Congo. Bob Colebunders was part of a team of international doctors who were treating Ebola patients in Kikwit, the epicenter of the 1995 outbreak. When a nurse who was tending to Ebola patients began to exhibit the symptoms of the disease, she was given a transfusion of blood from a survivor. She got better, so the team tried the same treatment on seven others. Of the eight who received transfusions, only one died—that's a much better survival rate than the 20 percent overall rate during the Kikwit outbreak.
Colebunders, who is now a professor of tropical diseases at the University of Antwerp in Belgium, says the results he saw in 1995 were hopeful but not entirely conclusive. "We don't know exactly why it had an effect," Colebunders says now of the transfusions. "It could be that it's the antibodies, but "¦ certainly it's clear that other factors were playing a role."
He says he is wary of using blood transfusion as a treatment for Ebola on a large scale, especially before further tests are conducted. He favors a gradual approach: The treatment could be rolled out "first on a relatively limited scale—well-documented—and then, depending on the results, we could consider scaling it up."
Transfusion, Colebunders says, is a stopgap measure until a more robust solution is available. "It's only in the meantime, because there is nothing, and this is readily available, that it should be done. Once there is better treatment, we should go to something else."
And even if it were proven that blood transfusion is an effective way of treating Ebola, it brings a number of obstacles that could be particularly hard to navigate because of the poor quality of some West African nations' health care systems.
There's the issue of voluntary consent: "You have to find people who have survived and who understand what they're doing, and willingly give that blood," says Harris. And if transfusions take off as a treatment, she says, there could be a risk to survivors, whose blood would suddenly become a valuable resource. "They could be actually at threat of being seen as a commodity."
Once willing volunteers are lined up, there are potential pitfalls associated with transferring the blood. It must be collected safely, using a sterile needle in a clean environment, and then screened for blood type (which must match that of the recipient) and the presence of other blood-borne viruses such as hepatitis and HIV. These are all basic requirements that almost any laboratory in the U.S. would meet, but such labs are not widely available in West Africa. "We're talking about some countries that have very, very limited facilities," says Harris.