Google Flu Trends, which was first released in the United States in November, tries to track the incidence of flu based on the ebb and flow of searches for keywords related to influenza. From their website :
“In the United States we have found a close relationship between how many people search for flu-related topics and how many people actually have flu symptoms. Of course, not every person who searches for “flu” is actually sick, but a pattern emerges when selected flu-related search queries from each state and region are added together.”
During the 2007-2008 flu season, an early version of Google Flu Trends was used to share results each week with the Epidemiology and Prevention Branch of the Influenza Division at US Centers for Disease Control and Prevention. Across each of the nine surveillance regions of the United States, Google Flu Trends were able to accurately estimate current flu levels one to two weeks faster online than published CDC reports. Google Flu Trends may provide an early-warning system for outbreaks of influenza in near real-time.
Google’s Experimental Flu Trends for Mexico was created in response to inquiries from public health officials regarding the current H1N1 outbreak (formerly poorly named as “swine flu”). It’s considered experimental because the information hasn’t been verified. But as they say on their website, “You’ll see our unverified estimates on the Experimental Flu Trends for Mexico page. We hope this may shed additional light on possible flu activity in states in Mexico…. Our up-to-date influenza estimates may enable public health officials and health professionals to better respond to seasonal epidemics and pandemics.”