Predicting the flu

Three more people in Minnesota have died as a result of complications from the flu, all had the mysterious “underlying medical conditions,” MPR (AP) reports today.

Meanwhile, the latest government survey finds that 1 in 5 children in the U.S. “had a flu-like illness earlier this month, and most of those cases likely were swine flu,” the Associated Press reported. Still planning on opening your front door to the kids on Halloween?

Try running the numbers on this and you’ll see how impossible it is to put the flu into any sort of historical context.

According to the Centers for Disease Control, 38,000 people a year in the U.S. die as a result of flu or associated complications (like pneumonia). But the CDC doesn’t really know this to be true since not all states have reported flu deaths and, if they do, they’re not all reported the same way.

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The CDC reset this year’s count to zero in August after revamping the mechanism for reporting hospitalizations and deaths. According to its Web site, there’ve been 292 deaths since the end of August. Minnesota says there’ve been 10 deaths here.

The CDC does track pediatric deaths and through last week, there have been 43 reported — about half the number of recent flu seasons and we’re only at the beginning of the flu season now. Let’s just say the CDC graphic-makers aren’t producing the most intuitive graphs on the subject (click for larger image):

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Nothing about the flu is predictable, it seems, including the arrival date of a flu vaccine. But that doesn’t stop health officials and other experts from making predictions, the LA Times notes:

Statistician Sherry Towers and Zhilan Feng of Purdue University reported last week in the journal Eurosurveillance that a mathematical model of the swine flu pandemic predicts the disease will peak this week.

But officials from the Centers for Disease Control and Prevention have emphasized repeatedly that trying to predict what any form of flu will do in the future will most likely be an exercise in futility.

“We may see in any particular community illness going down in the next several weeks, but we don’t know whether it is going to go up again,” Dr. Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Disease, said Tuesday.

If the statisticians are right, and the flu is peaking this week, then the number of pediatric deaths may be smaller than usual. If the current statistics from the CDC hold up for the entire flu season, the number of pediatric deaths will be substantially higher than usual.

Everyone’s guessing, and there appears to be no reliable historical context for what’s going on.

Some graphs from the Minnesota Department of Public Health try, like this one showing the number of doctor visits compared to previous years:

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But is that because of a difference in severity of the flu, or the fact that every news organization is talking about it constantly?

Probably the former if the results of viral cultures are an indication:

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