BROOKE GLADSTONE: This is On the Media. I'm Brooke Gladstone.

MIKE PESCA: And I'm Mike Pesca. This week brought reports that six members of an Indonesian family may have been killed by avian flu. That would bring the total number of deaths to 121, not this year, not in Indonesia, but worldwide ever. The number may not seem huge, but public health officials are quick to remind us that there is the potential risk that avian flu, if it mutates, could rival the 1918 pandemic that killed some 30 to 40 million people. Potential risk. That's a phrase you've probably heard a thousand or so times in stories about avian flu or mad cow, or west nile or smallpox. These diseases all carry a potential risk. Fair enough. But if risk is something bad that could happen, what's a potential risk? Something bad that could, could happen? Marc Siegel is a practicing internist and a professor of medicine at the New York University Medical School. He's a man who takes health risks seriously, but he's also on guard against a false alarm, which is the title of a book he's authored, subtitled "The Truth About the Epidemic Of Fear". Welcome to On the Media, Dr. Siegel.

DR. MARC SIEGEL: Thanks, Mike. Thanks for having me on.

MIKE PESCA: Let's talk about the biggest fear de jour, and right now everyone's talking about bird flu. There's an ABC Movie of the Week and the World Health Organization says bird flu could kill 150 million people. What do you say?

DR. MARC SIEGEL: Well, Mike, I think fear is supposed to be a warning system against imminent danger, and I think by always talking in doom and gloom terms, we send the public the message that something is about to happen. By doing that, we blur a lot of steps that would have to occur first. This current virus that we're obsessing over, the H5N1 virus, appears to be multiple mutations away from being able to pass easily human to human and even cause a pandemic. Secondly, we don't know what the effect is of modern technology on this virus, if it ever did cross the species barrier. Look, when a disease is new, when it's just coming out, it's normal for people to be afraid of it. That doesn't mean, though, that the bird flu is more of an imminent risk than something like tuberculosis, malaria. HIV/AIDS has killed 3.1 million people this year. I don't think we should take the eye off those balls.

MIKE PESCA: Now, I want to be clear. Do you think you and the epidemiologists who study bird flu every day actually disagree on what the potential for risk is?

DR. MARC SIEGEL: I think the answer to that is that the actual risk itself is always evolving. I mean, we found out over a year ago that this particular virus was similar in structure from the 1918 virus. That was worth being concerned about. But here's what we found out since then. Two studies that came out last month showed that it's multiple mutations away from being able to cross the species barrier. Another researcher looked at trying to manipulate it with similar genes from the 1918 virus, and he wasn't able to get it to take a human lung tissue. The other problem is we already have other viruses out there, flu viruses that do go human to human, and they could mutate while we're so focused on this one.

MIKE PESCA: In Slate, Gregg Easterbrook wrote a column that was basically in agreement with your basic point, but he did say that there's a justifiable reason for hype around bird flu. And this is what he said the justifiable reason was: "Recent experience shows pushing the panic button is an effective way to prevent a disease from taking hold". Well, if that's the case, is it really so bad if we push the panic button perhaps unnecessarily every now and again?

DR. MARC SIEGEL: I saw Gregg's article in Slate, and I thought it was excellent. But I actually am not sure that I agree that pushing the panic button helps. I mean, you take some recent examples like SARS. I don't think that there's any evidence that pushing the panic button on SARS did more than spend billions of dollars around the world, cost us money in terms of tourism, in terms of the Asian and Toronto economies. Now, what it did do, and this is a positive thing, I think it caused countries to work more closely at reporting cases and isolating sick people, because that's a really important thing that infectious disease has to do. That doesn't mean, though, that they somehow snuffed SARS and that they should take credit for it, because there's no evidence of that. It looks like SARS wasn't as infectious as we thought it was.

MIKE PESCA: This show has documented how journalists don't speak science so much, but what can journalists do? Can journalists push back against the World Health Organization?

DR. MARC SIEGEL: It means asking very smart questions to your officials that are giving their opinion. I think in bird flu, it's officials that have caused the hype and the hysteria, even more than the media has in this case. We have to learn a new language of how to communicate risk, so that we can say to the public, look, this is something we have to be concerned about and take seriously, but there is nothing imminent here. We seem to lose the last half of that sentence.

MIKE PESCA: Have you seen similarities or differences between, say, how America reports these risks and how western Europe reports these risks?

DR. MARC SIEGEL: You know, Mike, in the post-9/11 world, we here in America became very vulnerable. We felt susceptible. We were psychically wounded. We panic at the very first thing that comes along. Anthrax -- we overreacted to 22 cases and we all were afraid to open our mail. Then we were afraid of smallpox, which hasn't been here since the 1940's. You know, then it was SARS. I think with those issues, Europe and the rest of the world was not reacting to the same extent. But more recently, I mean, the media in Europe, I've looked at it very closely, and there's been a great deal of panic and over-reaction to bird flu, which has led, in part, to the fear of poultry in Europe, even though there wasn't a single human case. This seems to have toned down, and I think that there's a more consistent message out there of, let's inform you but be more cautious about it. So there was a huge difference initially, after 9/11, but right now it's been fairly similar around the world.

MIKE PESCA: Well, Dr. Marc Siegel, thanks very much.

DR. MARC SIEGEL: Thank you, Mike. Thanks for having me on.

MIKE PESCA: Dr. Marc Siegel is the author of "False Alarm: The Truth About the Epidemic Of Fear" and "Bird Flu: Everything You Need To Know About the Next Pandemic."