By the CDC’s latest “outpatient surveillance” estimates, roughly 5.6 percent of Americans visiting the doctor are reporting respiratory illnesses, or flu-like symptoms. That’s a large number, significantly higher than the national baseline of 2.2 percent or the 2.3 percent peak of last year’s mild flu season.
But it’s not entirely out of the ordinary. The figure approached 6 percent in the moderately severe 2007-2008 season and topped out at 7.7 percent in October 2009 in the midst of the H1N1 pandemic.
But here’s the thing: The CDC’s current estimates aren’t all that current. Because they are based on after-the-fact reports from more than 3,000 health care providers around the country, the numbers can tell us only how many people were suffering from the flu a couple weeks ago. Today’s CDC FluView figures, for instance, come from the week of Dec. 23. We won’t know until Friday how many people visited the doctor with respiratory symptoms during the week that began on Dec. 30.
That’s where Google comes in. In fall 2008, the company’s charitable arm, Google.org, unveiled Flu Trends, a site that scans millions of Google searches from around the world to track flu activity in near real time.
According to a study published in Nature in February 2009, the system can detect outbreaks nearly two weeks before they show up in the official CDC reports. And the site can tell you on any given day what countries, states, and even cities are likely seeing the largest number of cases.
Today, Flu Trends is painting a foreboding picture. On a global scale of green (minimal flu activity) to bright red (intense flu activity), the United States is the reddest country in the world. Zoom in, and the red stretches are almost unbroken across the country’s eastern two-thirds. (Hang in there, Connecticut!) Boston, New York, Philadelphia, Houston, and Denver are among a slew of cities tagged with the “intense” rating.