By Richard Knox

Lots of people get sniffles, sore throats, fever and other respiratory miseries this time of year. In a normal year, only about one person in four actually has laboratory-confirmed flu when samplings of nasal swabs from sick Americans are tested.

woman sneezing

Ah-choo! Is it the flu? (iStockphoto.com)


This year is different. The World Health Organization says more than 40 percent of Americans with "influenza-like illness" are testing positive for flu (and it's nearly always the new H1N1 flu). In some countries as many as 70 percent of nasal swabs turn up flu-positive.

That's pretty interesting, considering that at this point in the season last year, only 2.2 percent of the swabs tested postive.

So if you have respiratory symptoms this year, there's a better-than-usual chance it's the flu.

Keep in mind, though, that people with respiratory symptoms are not routinely tested for flu. These results come from spot sampling that the CDC does every year to get a sense of how much flu is out there in a given year.

Actually, your chance of having flu if you have the symptoms is probably even higher than 40 percent, says the WHO's Dr. Keiji Fukuda, who provided the new data during a Thursday teleconference with reporters.

That's because many nasal swabs that really contain flu viruses test negative because they were improperly handled. Others come from people who really did have the flu, but they had fought it off by the time the nasal swabs were taken. So the virus disappeared without a trace.

categories: Swine Flu (H1N1)

10:45 - November 5, 2009

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