Each week, millions of users around the world search for online health information. Google had found close relationship between how many people search for flu-related topics and how many people actually have flu symptoms. Google Flu Trends uses aggregated Google search data to estimate flu activity in your state up to two weeks faster than traditional systems.
Google compared query counts with data from a surveillance system managed by the U.S. Centers for Disease Control and Prevention (CDC) and discovered that some search queries tend to be popular exactly when flu season is happening.
So why bother with estimates from aggregated search queries? It turns out that traditional flu surveillance systems take 1-2 weeks to collect and release surveillance data, but Google search queries can be automatically counted very quickly. By making our flu estimates available each day, Google Flu Trends may provide an early-warning system for outbreaks of influenza.
