One kid gets the flu, a high school is closed for a week or more. Never mind that the kid is already better and that everyone in the high school has already been exposed--the tests didn't come back until well after the start of the illness.

I'm not an epidemiologist, and I'm not a doctor, but this seems a bit over-the-top.

So far, the "swine flu" has killed 20 people, 19 of them in Mexico and one in Texas after coming from Mexico. As flus go, this one isn't as nearly as bad as the myriad flus that have been wandering the globe this year.

Yet.

It's that last caveat that seems to be driving the professional disease types a wee bit batty. Infectious disease folks have been aware of this particular strain of flu for about five weeks, which is hardly long enough to figure out whether it's particularly virulent or lethal. So when a test comes back positive, the pros tell an entire community to shut down--but don't panic!

Even as the pros have been (relatively) low key, the rest of us have been going batshit. What is it about the flu that bugs us?

I think it's that this is a disease that theoretically could kill anyone. We're so used to going to the doctor for every little problem that we forget the fact that the best defense against illness and injury is the amazing ability of our bodies to heal themselves. Against the flu, we have no defense other than ourselves.

This situation is everyday life in most parts of the planet, where diseases like malaria kill millions each year. Except that there are cures for most malarial afflictions (which are caused by parasites), where as the flu is viral. Hospitals can treat the symptoms, but our bodies are the only thing that can get rid of the virus.

In the industrialized world, the birthrate is well below 2.1 children per family, the rate necessary to keep population steady. The U.S. has a higher birthrate, but we get a big bump from recent immigrants. Americans who have been in the country for at least two generations aren't having many kids, either.

Why is this? In a word, penicillin. Back before the discovery of antibiotics and other miracles of modern medicine, kids tended to die. You might have ten kids and hope two or three survive. A lot of folks make a big fuss about low life expectancy in ancient times, but if you made it to adulthood, you had a really good shot of making 60 or 70. It's all the children dying that kept life expectancy low.

Kids don't die anymore. At least, not nearly as much as they used to. There is a close correlation to a drop in childhood deaths and a drop in the birth rate. If people expect their kids to live, they have fewer kids.

And we do expect our kids to live. One of the few common diseases that threaten healthy children and adults is the flu. It comes out of nowhere and there is no surefire cure. You beat it, or you don't. The fact that most people beat it is hardly a comfort to those who don't.

The 1918 flu killed 18 to 20 million people, which is a lot, but in 1918 there were 1.8 billion people in the world. That means the flu killed one percent of the population. A study years later found that 97 percent of people who were alive in 1918 had antibodies to the flu. Which means that the 1918 flu, one of the worst ever, killed more than one percent of the people who got it. This doesn't sound like much, but it is. Every one of us knows hundreds of people. Imagine five or six or seven or whatever dropping dead instantly. Not comforting.

So fear of the flu is a rational thing. It's one of the few real threats to living a long and happy life. But is this flu worth the worry?

A better question is: Is there anything we can do?

I've read the instructions. Wash your hands, don't cough on people, etc. All reasonable enough. But still nowhere near any assurance that some random stranger passing by on the Metro won't accidentally hurl the one droplet of water vapor by way that floods the flu into my system.

All these handwashing warning and the like remind me of the "duct tape" approach to thwarting a terrorist attack. There's a point at which you simply have to live your life. We can take reasonable precautions, or we can hunker down and cower before an eight-gene menace.

I don't know about you, but I'm going to the park. And the preschool. And the Target. And the "dinosaur museum." If the flu really wants me, it's gonna get me. If there's anything we ought to have learned from 1918, it's that.

Jon Worley did not get a flu shot last winter--not that it would have helped, of course.