Blog | Wednesday, November 12, 2008

Googling the flu

The datameisters at Google say they can track potential flu epidemics two weeks earlier than the CDC by tracking people's searches for flu information online.

Google's non-profit arm,, is trying to apply its heft as the most popular search engine to tackle poverty, renewable energy and small-business growth. And now, they're applying the power of the millions of global users looking for health data to track the flu.

According to Google's blog, millions of users around the world search for online health information weekly. There are more flu-related searches during flu season, more allergy-related searches during allergy season, and more sunburn-related searches during the summer. A pattern emerges when all the flu-related search queries from each state and region are added together, Google says.

To test their hypothesis, Google compared search queries with CDC data to find out which searches occured during flu season, and then extrapolated that frequency provides an estimate how much flu is circulating. They used last year's flu season as a test and now claim to have accurately estimated flu levels one to two weeks faster than published CDC reports across the nine U.S. surveillance regions.

Additional details are available in a draft manuscript and a later version has been accepted in Nature.