John Brownstein is a big believer in Yelp.

That's because he uses it as a real-time surveillance tool that "paints a picture" of where illnesses may break out, he said during his keynote speech at mHealth Summit.  

The National Harbor, Md., summit was covered by MedPage Today.

Brownstein, an associate professor of pediatrics at Harvard Medical School's Center for BioInformatics, co-authored several studies on social media as a reflection of actual illness data. He authored a study published in Preventive Medicine that showed Yelp and an app called Open Table can give useful information on several levels.

Brownstein said 10 percent of restaurant reviews on Yelp are related to food-borne illness.

He said guesses by customers on Yelp as to what made them sick at a particular restaurant were remarkably accurate.

The study he conducted, called "Online Reports of Foodborne Illness Capture Foods Implicated in Official Foodborne Outbreak Reports," matched regions of reviewed restaurants to Centers For Disease Control statistics on food-borne illness.

Another study he conducted examined the Facebook "likes" of sedentary activities such as watching TV and movies, and compared them with "likes" for physical activity. 

That study showed that the sedentary "likes" mirrored the rate in the region studied.

Brownstein said Facebook, Twitter, online chat rooms, and the search terms typed into Wikipedia, can all help trace health issues. Based on that information he developed an innovative site called, that gives users information on outbreaks around the world.

The site uses social media, chat rooms, news sites and blogs to show data that oftentimes is overlooked by public health channels.

There are more such products in the works from his colleagues, Brownstein said. Flu Near You is another app Brownstein has co-developed. The app shows regions where there is a flu outbreak.

In his keynote address at the mHealth Summit, Brownstein said there will be continued research into the uses of social media as a tool to help healthcare research.