Flu Schmlu ... Forget the Media's Hype

Editor's note: below are two related blog posts which originally appeared on the public health blog Stayin' Alive.

Flu Schmlu

Yes, it is prudent to assume that someday, somehow, an emerging infectious disease pandemic will cause major global problems. I've said it a million times. However, contrary to the famous motto of Faber College, it is not always the case that Knowledge is Good, if it leads people to do stupid stuff.

Influenza is a common disease and a continual pain in the parts. The virus reproduces very sloppily so new strains keep emerging, which means we don't get the lifelong immunity we do from bouts with most viral diseases, which means that we can keep getting the flu year after year. Fortunately, for the vast majority of us, the vast majority of years, that means nothing worse than a few days off from work or school feeling like crap. (I highly recommend ginger tea.) It's a bummer, but that's the human condition.

We hear that something called "influenza/pneumonia" is the cause of about 63,000 deaths in the U.S. each year -- 10% of the number attributed to heart disease -- but that's highly misleading. (The reason they lump them together is that most of the time, it isn't clear whether people had the flu or not. Some of the people who die of respiratory infections did, but we don't generally have laboratory confirmation. People who are said to die of "influenza" for the most part die of bacterial pneumonia secondary to influenza or a different viral infection that appears similar.) The vast majority of these people are already sick and debilitated; many have advanced dementia and death from pneumonia is a mercy. Tragically, a small number of children also die each year from ordinary seasonal influenza. It would be nice to be able to stop that from happening but it's nothing new or different or strange.

Every once in a while a strain of influenza emerges that for reasons which are not well understood causes more severe disease than usual and/or spreads more easily and so causes unusually widespread disease. In 1918, the virus was unusually dangerous to otherwise healthy young men, less so to older folks. The hypothesis is that an overaggressive immune response explains this.

Okay, so what's going on right now? Probably absolutely nothing out of the ordinary. We're at the tail end of the flu season right now, and it happens to be that at this time a new strain of flu has been detected. The Mexican authorities seem to think it can cause unusually severe disease, but that has not been observed elsewhere and it is not clear whether that is really true in Mexico City either. When a small number of young men in Mexico City suddenly die of pneumonia, my first thought is HIV, not pandemic flu. (And it is a small number. The Mexican authorities have attributed 100 deaths to this virus, of which only 18 have been confirmed as actual swine flu infections. 20 million people live in Mexico City.) Influenza normally cannot survive in warm temperatures, which is why flu season ends in the spring. Unless this virus has some as yet completely unknown properties for which there is no evidence whatsoever, this outbreak is almost certainly going to die out on its own in no more than a couple of weeks. Even if it does not, there is no particular reason to think it will ever be much more than an annoyance.

Unless, of course, we proactively make sure that it is more than that. Which is exactly what is happening. I am not going to accuse the Mexican authorities of overreacting because I don't have the information they do, they have difficult judgments to make, so they did what they did. Undoubtedly, however, they have imposed a huge economic cost on the country, with the political and economic capital completely shut down, tourism effectively suspended, and small businesses without customers.