Wide Angle . H5N1 · Killer Flu . Transcript

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September 20, 2005: DR. ANTHONY FAUCI, director of the Institute for Allergy and Infectious Diseases at the National Institutes of Health, discusses the possibility of an avian flu pandemic with anchor Bill Moyers. BILL MOYERS: With me now is Dr. Anthony Fauci. He's been with the National Institutes of Health for 30 years now and is presently the director of the Institute for Allergy and Infectious Diseases. That means he's the commander in chief of the research to find vaccines that protect us against such major threats as flu and HIV/AIDS. Welcome to "Wide Angle." DR. ANTHONY FAUCI: Thank you. Good to be here. BILL MOYERS: What would you like for Americans to know about avian flu? DR. ANTHONY FAUCI: Well, Americans need to know that it is a threat, a real threat. It is an unpredictable infection, a pandemic flu, which really means a kind of flu to which the American public or the whole world, the global population has not been exposed to before. It is very different from the seasonal flu. It has the potential to be a major public health threat, but it is unpredictable. So you have to walk that balance of being prepared for something that may not come this year, may not come next year, but sooner or later knowing the history of how pandemic flus evolve over a period of time, over decades and decades, it will occur. So we need to be prepared. BILL MOYERS: When you saw the film did you think, "This could happen here?" DR. ANTHONY FAUCI: Well, I certainly think it can happen here and that's the reason why we really have to be very prepared. What is going on in Asia right now is the right constellation of events that increase the probability of there being a pandemic flu. We can't give you a number-- BILL MOYERS: Right. DR. ANTHONY FAUCI: --and say, "There's a ten or a 15 or a 20 or an 80 percent chance that there would be a pandemic flu which can spread readily from person to person." But the factors that are in place now in Asia that we saw on the film, the literally tens of millions of chickens in countries like Vietnam and Thailand and places like that that are infected. And the jumping of species, where it can jump, albeit inefficiently, from chickens to humans, the way it did in the film, and the very inefficient spread, very rarely, it's only occurred in a couple of cases, of human to human, it's evolving in a way that is making the threat more and more. BILL MOYERS: What's the difference between-- just to clarify some terms -- what's the difference between an epidemic and a pandemic? DR. ANTHONY FAUCI: You can have an epidemic in a state. You can have it in a region. You can have it in a country where the critical level of disease passes a certain threshold and we call that an epidemic threshold. When you're saying pandemic you're talking about that throughout the world. So a pandemic, we have a pandemic of HIV/AIDS now in the world. Virtually every country. A pandemic influenza would mean widespread infection essentially throughout every region of the world. BILL MOYERS: I lost a grandfather in the great flu epidemic of 1918. My wife lost a grandfather in that same epidemic. But it's correct to call that an epidemic, not a pandemic? DR. ANTHONY FAUCI: No. The 1918 was indeed a pandemic. BILL MOYERS: Really. DR. ANTHONY FAUCI: It was the mother of all pandemic flus, really. It was one of the worst in history. BILL MOYERS: So could you say if avian flu spreads as the film suggested it might and that you are warning us against, that it could be greater than the epidemic of 1918, the flu epidemic, pandemic? DR. ANTHONY FAUCI: Well, let me put it into some perspective. 1918 was a total public health catastrophe. There were 20 to 40-plus million people worldwide infected and a half a million to 750,000 in the United States. We have lesser pandemic flus in 1957 and then again in 1968. The one in 1957 had 70-plus thousand people died in the United States. In a regular, seasonal year, about 36,000 people die. Had less in 1968. So to have a pandemic flu it doesn't always have to be a catastrophe like in 1918. The problem with a pandemic potential is that it's unpredictable. So we're watching very closely what is going on in Southeast Asia now, and we're hoping that this virus doesn't assume the capability of efficiently and in a sustained manner going from human to human. If it does and the genetic changes will allow it to do that, we can't predict whether it'll turn into a 1918 type or a 1968 type. But the fact that we can't predict it means we need to be prepared for the worst. So when you hear public health officials very carefully scrutinizing what's going on in Southeast Asia and saying, "We really better be prepared because the potential of this is enormous." BILL MOYERS: What is the worst scenario? DR. ANTHONY FAUCI: Well, the worst scenario is that this virus that's circulating right now in Southeast Asia maintains its mortality rate. Right now there have been 112 cases in people with 57 deaths. So that's about a 50 percent mortality. BILL MOYERS: And that's high? DR. ANTHONY FAUCI: That's really high. Even the pandemic flu of 1918 only killed one to two percent of the people who were infected. What would likely would happen is as the virus genetically evolves to become more efficient in spreading from person to person or from chicken to person, it is likely that its virulence or its ability to kill, its mortality, would be less and less. Because viruses evolve in a way to self-propagate themselves. It's to no advantage of a virus to kill almost everybody it infects. It's the advantage of the virus to spread, and you can only spread when you infect people and they infect other people without necessarily killing them. So if you had 100 percent mortality, the potential pandemic would almost self-eliminate itself. What you need, the right ingredients, is something that spreads very rapidly but has a degree of mortality that's significant enough to cause a lot of deaths. So the worst scenario is that this evolves in two ways. It evolves in a way that it spreads very, very rapidly, and it keeps enough of its virulence to cause a lot of damage. BILL MOYERS: Sounds like a smart virus. DR. ANTHONY FAUCI: Well, you tend to think of microbes as thinking. They don't. They just genetically evolve in a way that selects for their own self-preservation. And that's what you mean when a microbe, in this case a virus, evolves. It's smart when it does that really, really well. BILL MOYERS: Have you seen the microbe? DR. ANTHONY FAUCI: Oh yeah. BILL MOYERS: Of the avian flu? DR. ANTHONY FAUCI: Oh yeah. BILL MOYERS: You've actually looked at it. DR. ANTHONY FAUCI: You look at it in an electron microscope. It looks like a little particle. It's got a little surrounding coat on the outside. It looks in many respects to be unitiated like any virus. They're very, very, very small particles. You know, bacteria you look [at] under a regular microscope. You could actually see them with certain stains. When you have a virus like influenza, you have to look at it under a very special microscope called an electron microscope. BILL MOYERS: Until the flu vaccine that I take now that I'm at that age, I used to get regularly -- almost every year I'd come down with the flu. DR. ANTHONY FAUCI: Right. BILL MOYERS: I would go to bed for three days, take some aspirin and drink lots of liquid and I'd be up and around in three or four days. What's the difference between this flu and that flu? DR. ANTHONY FAUCI: Well, the fundamental difference when you say a potentially pandemic flu is one to which the population of the world has never been exposed before. Let me give you some examples. We call this H5N1. Flus are designated by two major proteins, the hemagglutinin which is the H and the neuraminidase which is the N. And it gets certain numbers. The flu that you and I got exposed to for the last several years happens to be an H3N2. And now I'll tell you how it's different than H5N1. If we have a little bit of a change from last year to this year, or from two years ago to the next year, it has still been H3N2. It's the Fujian strain or the California strain or the Panama strain. So that when we get infected on a given year, even though we may get infected and sick, we still have some baseline immunity from either previous exposures in previous years or previous vaccinations. So even though we may get infected and we may get sick, our body is primed to ultimately suppress that virus. When you get H5 and N1, the H5N1 no one has ever experienced before. So when that virus gets to your body, you don't have any prime baseline immunity to come in and suppress it. So it can really do some significant damage in you before your immune system builds itself up enough to ultimately eliminate it. That's the fundamental difference between a pandemic flu that you've never experienced before and a seasonal flu where you experience some modification of that virus. BILL MOYERS: Right. So it is, if I may use this analogy, it is a smart virus but the body is smart too. DR. ANTHONY FAUCI: Yes. BILL MOYERS: And figures out how to respond and then the virus figures out how to respond to the body's response? DR. ANTHONY FAUCI: Well, that's what it does when it changes. Like for example, this season you have a certain type of an H3N2. As it circulates, it starts to do what we call drift. It changes enough that the body doesn't recognize it as exactly something it saw before, which is the fundamental reason why each year almost invariably you have to change your vaccine just a little bit. BILL MOYERS: Is this an apt analogy to say that we've never had a hurricane like Katrina before? So that when Katrina hit, we had prepared for hurricanes we had experienced but not one like this. DR. ANTHONY FAUCI: Well, yeah. And all analogies have their faults-- BILL MOYERS: I know. DR. ANTHONY FAUCI: --but that's a reasonable one; that it's something that the body has not experienced before. The body was waiting for the regular flu. Kind of knows how to handle it seasonally. Then you get a flu that it's never experienced before.

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Dr. Anthony Fauci, director of the Institute for Allergy and Infectious Diseases at the National Institutes of Health