DAVID GREENE, HOST:
Here's one measure of how fast the Ebola outbreak is still spreading. There have been about 400 more deaths since last week.
DON GONYEA, HOST:
The crisis in West Africa has spurred action on a number of experimental treatments. The drug-maker Johnson and Johnson announced this morning that it will speed up testing for a possible Ebola vaccine. Clinical trials could start early next year. The goal would be to use a vaccine in future outbreaks.
GREENE: That's because health officials hope the current outbreak will be under control by next year, but that could be optimistic. We had a chance to sit down yesterday with Dr. Margaret Chan. She's the director general of the World Health Organization, and she made clear this outbreak is far from over.
GREENE: You've said that this Ebola outbreak is racing ahead of our ability to control it. So how much worse do you expect this to get?
MARGARET CHAN: Well, as I've been saying, we expect to see the worst before we begin to see - you know, it will come down under control. We are not there yet.
GREENE: Best-case scenario, can the WHO at this point make a prediction for how long this outbreak is going to run and how many deaths we are likely to see?
CHAN: Well, we hope that, you know, within six to nine months we bring the outbreak under control in the three hardest-hit countries.
GREENE: Six to nine months, and how many people do we expect will die during that period?
CHAN: Well, it is - as I said, this is a severe disease. Fifty percent of the people infected will survive, and that's the good news. But 50 percent of them on average will die. We project in the next six months, we're going to see a minimum of 20,000 cases. So and that gives us a sense of where we are, but let me emphasize...
GREENE: Of 10,000 people dying roughly.
CHAN: Well, I mean that's a estimate and a guesstimate.
GREENE: Let me ask you about the possibility for mutation here. Is this virus mutating in a way that could be very dangerous, that could make it spread faster?
CHAN: The very nature of this virus is - it is on a constant basis making changes, and people use the term mutation. And we are now looking at the virus - the sequence very carefully and identify how many changes they have made. According to the scientists, this virus is changing. It is changing. But whether they are changing to cause a difference in the way it is easier to transmit or making it more severe, I don't think at this point in time the scientific community have a definitive answer.
GREENE: Could it change in a very alarming way, such as being transmitted through the air?
CHAN: Well, we hope not. We don't see the evidence at this point in time, but it is important to continuously to monitor the changes.
GREENE: It's scary that you're not able to rule out that possibility.
CHAN: Well, it can change to make it less severe, too, and virus being a very changeable, mutating, adapting, so it can go both ways.
GREENE: That's Dr. Margaret Chan, she's director general of the World Health Organization, and you can hear more of our conversation with her elsewhere in the program. We talked about the international response to the epidemic and whether it should have been more urgent. Transcript provided by NPR, Copyright NPR.