JACKI LYDEN, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Jacki Lyden.
In recent months, an especially virulent string of the bird flu has spread from Southeast Asia north of China and into Russia and Kazakhstan. This strain, known as H5N1, can infect humans as well as birds and it can be deadly for them. The World Health Organization is taking the threat of a bird flu pandemic very seriously, and this past week, the Swiss drugmaker Roche said it would donate enough of the drug Tamiflu to the World Health Organization to treat three million people should they become infected. Dr. Margaret Chan is the World Health Organization's director for pandemic influenza preparedness and she joins me now from Geneva.
Welcome, Dr. Chan.
Dr. MARGARET CHAN (World Health Organization): Hi, Jacki.
LYDEN: We know that dozens of people have already died from the so-called bird flu among people, but it would seem that it's a long way away from being a pandemic. So maybe we could begin by asking you to explain what the definition of a pandemic is.
Dr. CHAN: Normally it would require certain criteria. Number one, you need to have the emergence of a new virus strain and that has already occurred. That is the H5N1. And the second thing we would be looking for is that it has jumped from bird to human, and that has already occurred. Now the third thing we are looking for now is the ability of this virus to have what we call sustained human-to-human transmission. So in other words, if the virus mutates to such an extent that it has the ability to cause infection in people and from people to people, then that is the early sign of a pandemic.
LYDEN: Does a pandemic have to claim a certain number of lives to be classified that way? Is there other numbers and time records that have to be established to make it a pandemic?
Dr. CHAN: No. I mean, it's not the number that counts, you know, whether or not it is a pandemic. As I said, if you have a new virus that the world's people does not have immunity, that is, you know, important, and if that virus has jumped to affect human and if it cause infection, you know, around the world, then that's why we call it pandemic.
LYDEN: And while we don't want to be alarmist, more than half the people who got it died. The mortality rate was 55 percent I believe.
Dr. CHAN: It is indeed very serious. Up to this point in time, 112 human cases were reported with 57 deaths, but, you know, I mean, Jacki, it is important for us to understand pandemic influenza--and we have learned it from history--in the past that it took the world by surprise. We did not get early warnings. This is perhaps the first occasion we are getting some early warning and people will say that, `Are you sure it is going to happen?' The answer is we don't know. We know a pandemic will happen. It's just that we don't know how soon and where it would start. So the investment in preparing for a pandemic is a very difficult and very tough decision. I think we have a duty and a responsibility to get prepared.
LYDEN: When you take a look at what preventative efforts are being done--I read a comment that it would be thrilling were it not so terrifying--there are experimental vaccines which people are working on against H5N1. Does that help you sleep better at night?
Dr. CHAN: H5N1 vaccine is being very diligently pursued by many institutions and also vaccine companies. They're working on the assumption that H5N1 would be the likely candidate for the next pandemic, but I must emphasize it does not have to be the case. It could be another virus, but nonetheless, the development on H5N1 vaccine is a positive step in the right direction.
LYDEN: Well, Dr. Chan, thanks for speaking with us. Dr. Margaret Chan is the World Health Organization's director for the Department of Communicable Disease Surveillance and Response.
Dr. Chan, thanks very, very much for talking to us today.
Dr. CHAN: It's my pleasure, Jacki.