Google uses online queries to see where flu interest is peaking

Chances are, before your patients come to you with flu-related symptoms, they have already done an online search about them.

That is the assumption behind a new tool launched by Google, the search engine company that has been expanding into health care over the past few years, including launching an online personal health record.

Google Flu Trends, launched in November, collects the aggregate data for flu-related search terms to pinpoint specific areas of flu outbreak. Unlike reports from the Centers for Disease Control and Prevention, which normally take a few weeks to compile and release, Google flu data are updated daily.

The company says the service could alert physicians and public health officials when an influenza outbreak has occurred. The CDC is collaborating with Google on the Flu Trends project.

"The CDC and state Web sites are weeks or up to a month late on reporting trends, so they are more useful for historical data as opposed to making decisions at the time you look at [the data]," said George Voigtlander, MD, a family physician with Pawnee County Rural Health in Pawnee City, Neb.

Google says the tool uses aggregate data from hundreds of millions of searches over time to come up with estimated percentages of people with influenza-like illnesses. The data are updated daily and can be accessed by anyone online (link).

The Web page displays a map that shows specific information for each state, along with a fever chart that shows historical flu outbreak data for that region and time.

Dr. Voigtlander, who has no affiliation with Google Flu Trends, said that if it works correctly, it can give physicians time to reach those at-risk patients who might have missed their flu shots. Knowing an outbreak is occurring could also give public health officials and the media time to promote preventive measures, he said.

Simple reminders to take preventive measures such as washing hands regularly could reduce the impact of an outbreak, Dr. Voigtlander said.

System not foolproof

Brian Bachelder, MD, a family physician in Mt. Gilead, Ohio, said the tool would be most effective if data were used by entities such as local health departments or medical societies, which could send e-mails alerting physicians to a possible outbreak.

"The problem is just because the information is available, it doesn't mean physicians are checking it," said Dr. Bachelder, who is not affiliated with Google Flu Trends. The data should also be used as a predictor and not as an absolute truth, he said.

The company used historical logs of online searches from 2003 to 2008 to compute similar data, which it compared with CDC data. Google says the tool generated fairly accurate data. But it did acknowledge limitations of the technology in an academic paper published in Nature magazine in November. The "system is susceptible to false alerts caused by a sudden increase in [influenza-like illness] related queries. An unusual event, such as a drug recall for a popular cold or flu remedy, could cause such a false alert."

Dr. Bachelder said the system could also miss a potential outbreak in areas that have low Internet usage.

Others say Google's ability to protect user privacy is a bigger concern.

"Flu Trends uses aggregations of search query data which contain no information that can identify users personally," said Mike Yang, senior product counsel at Google.

But privacy advocates Patient Privacy Rights and the Electronic Privacy Information Center want Google to show how the company can ensure aggregate data cannot be reidentified. The groups sent a joint letter to CEO Eric Schmidt asking Google to release its search algorithms. Google has refused the request.

Another flu monitoring system was recently released by Sermo, the social networking site for physicians. Sermo's system relies on physicians reporting influenza cases they have treated. Users can report and view those data on Sermo's Web site.

Sermo and the American Medical Association have a partnership that allows AMA members access to Sermo and allows AMNews stories to be linked directly to Sermo's Web site (link).