Track the Flu in Your Area With... Google?

  • I am a health care professional, and when I want health information on the Web, I generally seek out what I think of as reliable health information sources, such as the Centers for Disease Control (CDC) or the National Institutes of Health (and HealthCentral, of course).


    So I read an article recently with interest. It told how Google is now claiming to have more timely information on the incidence of flu throughout the U.S. than health sources. That got my attention, because avoiding the flu when you have asthma is a high priority during the winter months. So, I thought I'd check it out to learn more.

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    I found that has created a site on flu trends. Here is what it says there:

    "We've found that certain search terms are good indicators of flu activity. Google Flu Trends uses aggregated Google search data to estimate flu activity in your state up to two weeks faster than traditional systems."

    It was pretty fascinating. Last year, during flu season, Google tracked flu-related searches and found that geographically-related searches usually peaked before the CDC reported increases in flu cases for that area. In fact, Google shared their information with the CDC to help them with flu surveillance.

    The CDC uses different methods to track influenza across the US each year. One way is to rely on reporting from a network of more than 1500 doctors who see 16 million patients each year.The doctors are asked to keep track of the percentage of their patients who have flu-like illnesses. Then, the CDC and state health departments collect and summarize this data to estimate overall flu activity across the United States.


    But this method can be slow, taking a week or more to pull together the report each time. Google search queries can be counted very quickly--and automatically. So, Google Flu Trends can possibly be used as an early-warning system for outbreaks of the flu.


    And having such an early warning system can help health professionals better respond to epidemics or unusual strains of the flu. As an individual, you can also use the Google Flu Trends data to track what's going on in your area of the US.


    CDC Caveat About Google Flu Trends


    However, the CDC cautions that "there are important limitations to Google Flu Trends. Flu Trends is a useful adjunct to the current CDC surveillance systems, but it should not be considered a replacement." The CDC goes on to say that although Google's data is more timely and objective, evaluation of the data quality is more difficult.


    Google assumes that an increase in web activity about the flu translates to an increase in flu cases in an area. But the CDC points out that spikes might occur because of media attention about the flu or other related issues, even when cases have not increased.  In addition, Internet trends might not accurately reflect what's happening in one of the highest risk groups for the flu, the elderly, as they may not be using the Internet as much as younger people do.


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    In summary, the CDC is not saying you should ignore Google's Flu Trends. They're just saying don't consider the data to be written in stone. It's about trends, not absolute facts.


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    Preventing the flu is essential for people who have asthma. Hopefully, by now you've received your annual flu shot. If not, check with your doctor or your local pharmacy to see when you can get one. It's safe, barely hurts and will keep you healthy this flu season.


    But, if for some reason, you can't or don't get a flu shot, then using Google Flu Trends will help you know when it becomes extremely important in your area to avoid people who might have the flu, to use good handwashing technique and to be alert for signs and symptoms of the flu.

Published On: November 30, 2008