When those around them are sick, or when they have caught something themselves, people get worried. With the Internet becoming a primary source of information for many, heading over to the computer to Google about an illness might be the next logical step to ease that anxiety.
Based on trends in the millions of search queries made every day, Google has been providing their own estimates of flu activity since November 2009—and are offering the service to a growing number of countries. This past Tuesday, they added a detailed map view for the U.S. that includes flu levels across 121 cities, including New York City, San Francisco, and Chicago.
In the U.S., Google tracking and estimating has been validated by the statistics on influenza-like illness (ILI) from the Centers for Disease Control and Prevention (CDC). By comparing flu estimates against threshold or baseline level activity throughout the U.S., Google assigns categories of severity of ILI to each region. Countries where Google estimates have not yet been validated are being labeled as experimental.
Local health officials can request more information on Google Flu Trends for their own country or region by filling out an online form. To be added to the program, data on ILI, acute respiratory infection, and/or laboratory-confirmed influenza case counts for the past three to five years is required.