Answering Your Questions About Ebola Treatments And Vaccines

Answering Your Questions About Ebola Treatments And Vaccines

6:43pm Oct 10, 2014
Icon Genetics' Dr. Frank Thieme selects samples of Nicotiana benthamiana, a relative of tobacco, growing in a company greenhouse in Halle, Germany. The company uses the plants to produce antibodies that could be helpful for increasing supplies of ZMapp.
Icon Genetics' Dr. Frank Thieme selects samples of Nicotiana benthamiana, a relative of tobacco, growing in a company greenhouse in Halle, Germany. The company uses the plants to produce antibodies that could be helpful for increasing supplies of
Sean Gallup / Getty Images

This week, All Things Considered asked listeners to send in their questions about Ebola treatment, drugs and vaccines. Here's a lightly edited summary of the conversation about the results, with questions posed by host Melissa Block and answers from NPR Science Correspondent Richard Harris.

Andrea Asuaje of Palm Beach Gardens, Fla. asks, how exactly are Ebola patients treated for the disease, aside from isolation?

The most effective treatment available now is simply to treat the symptoms. This is called supportive care. It means giving patients intravenous fluids and salts and minerals they lose as a result of being so sick. They may also get oxygen and antibiotics, if they have a bacterial infection. As for drugs to knock out the Ebola virus itself – there is nothing proven on the shelves right now

Nothing proven, but what about experimental drugs?

There are several, and they fall into three categories. First, there are antibodies that boost the immune system. And ZMapp is the prime example. Second, there are antiviral drugs that work against HIV or other viruses. For example, Jason Beaubien reports that one doctor in Africa is trying the HIV drug lamivudine in his patients. And third, there are experimental drugs that bind to the Ebola virus' genetic material. These are theoretically appealing, but there's no proof they work, either.

You mentioned ZMapp. We've heard that the supply of that drug has been exhausted. Is that the case?

Only a small quantity of this drug was ever made. The company that developed it, Mapp Biopharmaceutical, says it has distributed all its supplies. But there may be a few doses stashed away by the World Health Organization or other agencies. They're playing that close to the vest.

Do we know if any of these treatments actually work?

We have no idea. The number of people treated is simply too small. Some people have lived, some have died. There's no saying whether any drug has tipped that balance at all. That said, scientists are trying to ramp up studies in Africa, to try these drugs in many more sick patients. Those tests could begin by the end of November at the earliest, and it may take a while to get results.

Once an effective treatment is found, how quickly might it be scaled up, so it could get to the places that need it the most?

Nothing could be scaled up as quickly as we would want it. And the speed depends on the drug in question. ZMapp is produced in genetically modified tobacco plants, and they take time to grow. There are efforts now to find other ways to produce it. If one of the regular antiviral drugs happens to work, those can be produced fairly quickly. The potential drugs that bind to the virus' RNA will take months to ramp up if they prove to be effective.

Let's turn to another listener question, from Ajay Gupta of Cupertino Calif. He asks whether people lucky enough to be cured of Ebola, have built any immunity to it.

Yes, they have. The Centers for Disease Control and Prevention says they're immune from this strain of Ebola for at least 10 years, possibly longer. That's why those people are being recruited to some of the more dangerous jobs in West Africa.

Following up on that, we've reported that Ebola survivor Kent Brantley donated some of his blood plasma to patients with Ebola - including the NBC cameraman now hospitalized in Nebraska. How effective is this as a treatment?

Again, we don't know, but we can say there's a solid theoretical underpinning for that — in fact this technique was widely used before antibiotics were available. If you've ever had a gamma-globulin shot, you've essentially had this kind of serum treatment. There is a bit of experience with Ebola and that has produced hopeful results, but if the treatment works, it would be a logistical nightmare to produce this serum in any volume, particularly in West Africa where the health care system today is barely functional.

Listener Daniel Johnson, Jr. of Cincinnati asks: "Can you update us on progress that's been made to get a vaccine developed?" He's asking about a preventive vaccine, not a treatment for people already infected.

One vaccine is already being tested for safety in a small number of volunteers, here in the United States and in West Africa. That's produced by GlaxoSmithKline. A second vaccine from a small biotech company called NewLink Genetics is under development, but company isn't saying whether it's actually being tested in people yet; and Johnson and Johnson is working on a third potential vaccine, but it won't be ready for testing until sometime next spring earliest.

There have been about two dozen outbreaks of Ebola since 1976. Why don't we have a vaccine already?

Every outbreak before this one was quickly brought under control simply by isolating sick people to stop the spread of Ebola. That said, the U.S. government has been funding both vaccine and drug studies for more than a decade in case Ebola becomes a biological weapon. That research is now being accelerated in response to the humanitarian crisis in West Africa.

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Transcript

MELISSA BLOCK, HOST:

Last Friday on the program, we answered some of the questions you sent us about Ebola and today we'll take on a few more, specifically about treatment for the disease. And to do that, I'm joined by our science correspondent Richard Harris. Welcome, Richard.

RICHARD HARRIS, BYLINE: Hi, Melissa.

BLOCK: Now, let's start with a question that was sent in by Andrea Asuaje of Palm Beach Gardens, Florida, and she asks this - how exactly are Ebola patients treated for the disease, aside from isolation?

HARRIS: Well, of course, everyone is interested to learn about drugs that are specific to treat Ebola but in truth the most effective treatment available right now is to treat the symptoms. This is called supportive care, it means making sure people get IV drips, to give them plenty of fluids, to replace the salts and minerals they lose by being so sick. They get oxygen if they need that and if they get an unrelated bacterial infection they'll get an antibiotic for that. As for drugs to knock out the Ebola virus itself, there is nothing proven on the shelves right now.

BLOCK: Nothing proven, Richard, but we've been hearing a lot about experimental drugs that are being used.

HARRIS: Indeed we have, yeah. And they fall into three categories. First, are the antibodies that boost the immune system - ZMapp is an example of a drug that does that. Second are antiviral drugs that work against other diseases, like HIV or hepatitis. At this point, those are quite speculative but we just heard in Jason's piece the people are trying that in Africa as well. And third, drugs that bind to the Ebola virus's genetic material. These are theoretically very appealing but again there's no proof that they actually work either.

BLOCK: One of the drugs that you mentioned, Richard, ZMapp - earlier on in this we heard the supply of that drug had run out. Is that still the case?

HARRIS: Well, the company says its supplies are exhausted but in fact there may still be a few cases here and there, stashed away by the WHO or other health organizations. They're playing that one very close to the vest.

BLOCK: So these drugs are experimental. They are being used. Is there any proof that they actually work?

HARRIS: Well, actually we have no idea right now. The sample size is simply too small. Some people who've taken them have lived, some have died and there's no saying really whether the drug has tipped that balance at all. But that said, scientists are trying to ramp up studies in Africa with plenty of sick patients. And those could begin by the end of November, at the very earliest. So we might get answers out of that but not immediately.

BLOCK: Well, say they do find an effective treatment, right? It's proved to work. How quickly could that be scaled up so it could get to the places that need it the most and need it fast?

HARRIS: Well, not fast enough is the short answer. The longer answer is it also depends on the drug. The ZMapp is grown in genetically modified tobacco plants and that's a long process to produce the drug. The company and others are looking at more conventional biotech production methods to speed that up but still it'll take a while. If one of the regular antiviral drugs happen to work, well, those can be produced fairly rapidly, so that would be hopeful. And production of the drugs that bind to the viruses RNA would take a long time to ramp up as well. So it really depends on the drug.

BLOCK: Let's turn to another question sent in by a listener, Richard. This is from Ajay Gupta of Cupertino California and he asks people lucky enough to be cured of Ebola, have they built any immunity to it? We do get a lot of questions about this.

HARRIS: And the answer is yes they do build up immunity. The CDC says these people are likely immune from the strain of Ebola for at least 10 years and possibly longer. And for that reason, these people are being recruited to take on some of the more dangerous jobs in West Africa.

BLOCK: And because they're immune, that leads to another question because the blood plasma from some patients who have survived Ebola has been used to treat other patients. We know that Kent Brantly, the doctor, donated some of his blood to the NBC cameraman who has Ebola, also to another aid worker. How effective is blood plasma of survivors as a treatment?

HARRIS: Well, we don't really know the answer to its effectiveness but we do know that there's a solid theoretical underpinning for it. In fact, this technique was actually used quite widely before antibiotics were invented. If you ever had a gamma globulin shot you've essentially had this kind of serum treatment. There's a small amount of experience with Ebola and it is hopeful. But the problem is it's a really logistical nightmare to produce the serum in any volume, particularly in Africa where the health care system is barely functional to begin with.

BLOCK: Here's another question from a listener, Richard. This is from Daniel Johnson, Jr., of Cincinnati, Ohio, who asks this. Can you update us on progress that's been made to get a vaccine developed? In other words, not a treatment to cure Ebola, Richard, but a vaccine to keep us from getting the disease in the first place.

HARRIS: Right. And the answer is one vaccine is already being tested for safety in a small number of volunteers. It's made by GlaxoSmithKline. It's being tested here in the U.S. and they're starting the safety tests in Africa. The second vaccine from a small biotech company is under development. I called the company today they won't say if it's actually being tested as of yet. And Johnson & Johnson is working on a third vaccine but they say it won't be ready for testing until sometime next spring, at the earliest.

BLOCK: This is not a new disease, Richard. Ebola's been around since 1976. There've been a couple dozen outbreaks. Why isn't there a vaccine yet?

HARRIS: Well, one reason is every outbreak before this one was quickly brought under control simply by isolating sick people to stop the spread of the disease. So a vaccine wasn't really necessary. That said, the U.S. government has been funding both vaccine and drug studies in case Ebola becomes a biological weapon. That research now is being accelerated in response to the humanitarian crisis in West Africa.

BLOCK: OK, NPR science correspondent Richard Harris. Richard, thanks for answering these questions and thanks to our listeners for sending them in.

HARRIS: Good to be with you. Transcript provided by NPR, Copyright NPR.

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