Google developed a flu tracker called Google Flu trends.  It was developed with the help of  the U.S. Centers for Disease Control and Prevention (CDC) and is based on the number of search queries made about influenza. Google said it noticed that there was a relationship between the frequency of search queries and the number of people who are experiencing flu-like symptoms each week.

Our team found that certain aggregated search queries tend to be very common during flu season each year. We compared these aggregated queries against data provided by the U.S. Centers for Disease Control and Prevention (CDC), and we found that there’s a very close relationship between the frequency of these search queries and the number of people who are experiencing flu-like symptoms each week. As a result, if we tally each day’s flu-related search queries, we can estimate how many people have a flu-like illness. Based on this discovery, we have launched Google Flu Trends, where you can find up-to-date influenza-related activity estimates for each of the 50 states in the U.S. [via Google Blog]

Instead of the one or two week delay that the traditional flu surveillance systems have, Google said its reports will be updated daily and may provide an early warning system for influenza outbreaks.

The CDC does a great job of surveying real doctors and patients to accurately track the flu, 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.

Try it at www.google.org/flutrends

Influenza, also known as “flu” is responsible for up to 500,000 deaths worldwide each year.