Google.org recently launched a new source for flu data called Google Flu Trends. Flu activity is estimated by the number of Internet searches for flu information. This may correlate with the number of people having flu like illness. CDC and states now collect data from outpatient visits for flu like illness, laboratory reports of specimens testing positive for influenza, as well as reported outbreaks of influenza.
According to Google.org, they were able to estimate the 2007-2008 flu activity 1-2 weeks faster than CDC published reports. Some states monitor daily influenza like illness activity through syndromic surveillance which may be more timely than the published CDC reports. Also some state health departments are looking at data on over the counter medication sales.
Early warning allows state and local health officials to put into effect prevention and control activities as well as help people take appropriate precautions if flu is in their area.
The unique aspect of the Google flu surveillance is that it looks at the both the population that is seen by a clinician and those that are not seen by a clinician for their symptoms.
Google.org adds to the growing sources of innovative sources of health data such as ProMED-mail and Healthmap and I applaud their efforts. It will be interesting to follow this data through the coming flu season and determine how it can be used to benefit health.