With the media pumping out story after fevered story of a unique and "deadly" new strain of influenza sweeping the globe -- tossing words like "pandemic" around with little in the way of context -- you'd have to be a Vulcan not to experience just a touch of panic. But is this flu really so scary?

Any virus that's new to the human population poses a potential danger. But perhaps the most striking aspect of the swine flu quasi-panic is, if it had emerged just a few short years ago, we would have gone about our lives without any sense that anything unusual was even under way.

After all, millions of people around the world get the flu each year, and tens of thousands die as a result -- most of them very old or very young or people whose immune systems are already compromised.

The vast majority of people who catch a case of flu feel like crap for a few days or a week, and then they recover.  So far, the swine flu is no different -- it's not particularly virulent, nor is it deadlier than the strains commonly referred to as "seasonal flu" (although Mexican authorities initially thought it was for reasons that are not entirely clear).

Viruses mutate, intermingle with other strains and adapt, and the H1N1 flu is a new one -- a "zoonotic" virus that has leaped from pigs to humans. So it's always possible that the swine flu could become a genuinely dangerous phenomenon.

But so far there's no evidence to indicate that that's a likely scenario. In fact, researchers at the University of Maryland conducted a study that concluded the swine flu is less likely to recombine with other strains; the Los Angeles Times reported that the results should ease "fears that the pandemic H1N1 influenza virus will ... mutate into a more lethal form."

And if the swine flu -- H1N1 -- had hit just 10 short years ago, we would not have gone about our lives as if nothing was amiss. It's only due to stepped up efforts to screen for viruses after the SARS and "avian flu" scares, and our relatively new ability to quickly (and inexpensively) determine a virus's genome, that we know something other than the so-called "seasonal flu" exists at all. 

None of this has prevented the media from engaging in a full-blown Y2K-style panic. Every time a new case of flu is identified as being caused by the H1N1 strain, every time an unfortunate person dies of it, every time a public health official releases a new statistic about its spread or a school is shut down, a media feeding frenzy has followed.

It's true that the H1N1 strain has displayed a few unusual characteristics. There have been fewer lethal cases among infants and more among non-elderly adults than one would expect based on our experience with other strains of influenza. But looking at its impact on the population as a whole, the H1N1 virus has in no way proved to be more dangerous than the seasonal flu. 

Rarely is the actual threat posed by swine flu put into any statistical context.

So consider this: According to the European Center for Disease Control, there have been 4,092 confirmed deaths from swine flu around the world through Sept. 1. ("Confirmed" deaths is a dubious figure, but I'll use it for the sake of argument.)

If the same rate were to hold out for the rest of the year, that number would grow to 6,138 for 2009. That would mean you'd have approximately four times the chance of getting killed by a lightning strike (in an average year), and would be 200 times more likely to die in a car crash than to succumb to the swine flu. (Actually, this underestimates the likelihood of dying in a car crash, because anyone can catch a virus but not everyone gets around in a motor vehicle.)

Global deaths from malaria are estimated at 1.5 million to 3 million -- 2,500 times the projected toll from swine flu -- but you'll never see breaking news about someone dying of malaria splashed across the bottom of the screen of a cable newscast.

Perhaps the most exaggerated fear is that humanity might face a repeat of the 1918 flu pandemic, which may have led to the deaths of as many as 100 million people worldwide. That is partly due to the genetic similarity of swine flu to the virus that caused the 1918 pandemic, and also because the 1918 "Spanish flu" emerged at the end of the (Northern hemisphere's) normal flu season, and then re-emerged with deadly effect the following year.

But the comparison is nothing short of ludicrous -- the "Spanish flu" pandemic predated the advent of antibiotics and vaccines. What's more, most of the deaths in 1918 are believed to have been not a direct result of the flu but rather of secondary infections -- primarily pneumonia. In the era of modern medicine, even a similarly virulent strain of influenza would lead to a small fraction of the Spanish flu's mortality, if it were to hit today.

None of this is to suggest that swine flu doesn't pose any threat -- or that it's 100 percent certain that it won't mutate into something more dangerous. And any pandemic that causes people to change their behaviors can certainly cause huge disruptions to travel, trade and other activities that we take for granted.

But fear of a deadly pandemic is far more likely to cause real problems than the underlying disease.

In fact, that is exactly what has happened since the swine flu was first identified in 2008. Writing in the New England Journal of Medicine (subscription required), Lawrence Gostin, a Georgetown law professor who specializes in public health issues, notes: "epidemics often bring out irrational fears and discriminatory behaviors among individuals and governments."

Citing Gostin, Bart Laws, a medical sociologist at Tufts University, listed just a few of the excessive reactions that followed the emergence of the flu last year:

• China and Hong Kong quarantined travelers from North America, including 22 Canadian students with no symptoms, 300 guests and employees who happened to be in a hotel where a Mexican man was isolated, and everybody in Singapore who happened to have visited Mexico ...

• "Social distancing" measures included closure of 700 schools in the U.S., disrupting the education of 245,000 children ...

• Numerous countries restricted travel to and from Mexico and banned meat from North America, causing economic damage. In fact, Mexico's GNP declined by up to 0.5 percent in a few weeks.

• Egypt culled 400,000 pigs, an act of irrational discrimination against the country's Christian minority

On a somewhat lighter note, Reuters reported in May that "Afghanistan's only known pig has been locked in a room, away from visitors to Kabul zoo where it normally grazes beside deer and goats, because people are worried it could infect them with the virus popularly known as swine flu."

 

Fear Itself

Public-health experts have long understood that what differentiates a minor outbreak of disease from what they call a "catastrophic infectious disease outbreak" has as much to do with how society reacts to the illness as it does to the ease with which a pathogen is spread, its lethality or the existence of a cure.

Avoiding unnecessary and destructive panic depends on the quality of public-health officials' statements, the media getting the story right and the degree to which solid information is disseminated to health providers. 

Panic itself is, to a large degree, what makes an outbreak "catastrophic." It causes individuals and institutions to act irrationally -- to cease activities that are necessary for society to function smoothly. It sends people running to emergency rooms when they get a sniffle, overwhelming health care systems at the worst possible time.

Tufts' Laws has studied people's perception of risk -- what makes people terrified of something that is highly unlikely to hurt them (the occasional frenzy of shark-attack stories in the media, for example), while not worrying at all about far more dangerous activities like smoking cigarettes.

"One of the most powerful factors," he writes, "is social amplification of risk. Worries can be contagious and rapidly infect people within a social group. In modern society, the mass media are by far the most powerful carriers of contagion."

And the media are getting plenty of grist for their sensationalist mills.

In April, Homeland Security Chief Janet Napolitano called a press conference and declared a public-health emergency. In August, officials for the Centers for Disease Control warned that H1N1 could infect half of the U.S. population and kill 90,000 Americans by year's end. CDC officials estimated that 1 in 10 New Yorkers had contracted the virus this spring.

Meanwhile, the Observer, a British tabloid, breathlessly citing a leaked U.N. report, offered the specter of "millions" of rotting corpses and "anarchy" spreading across the developing world.

Unsurprisingly, people's fears of the flu are growing with every sensational headline.

In May, 1 in 5 respondents told Gallup that they expected a family member to contract the swine flu; by August that number had almost doubled. Over those same months, belief that the government was able to handle the situation dropped by 14 points -- from 74 percent to 60 percent.

Exaggerated fear has potential consequences beyond overwhelming ERs with nervous patients who should be resting at home consuming soup.

In mid-July, a Health and Human Services advisory committee "strongly recommended that [HHS Secretary Kathleen] Sebelius give the green light to vaccine production by Aug. 15 -- before safety and dosing tests are finished." The U.S. government ordered 195 million doses of a new H1N1 vaccine, which is being fast-tracked through the normal drug development and approval process. Whether that proves to be a problem or turns out to have been justified remains to be seen.

The take-away from all this is that the best cure for swine flu hysteria may be a healthy dose of salt.

When the news trumpets the latest fatality, remember that through the end of April, while not a single American had died as a result of the swine flu, the CDC estimated that 13,000 had already succumbed to complications arising from the plain old vanilla "seasonal flu."

Public-health officials, epidemiologists and clinicians have to worry about H1N1. As things stand, you really don't.