Crowdsourcing Food Poisoning; Yelping About Your Vomit

From the informatics experts at Children's Hospital Boston who created Health Map to track local and global disease outbreaks comes another novel proposal: tracking food-borne illness through Yelp. Here's their pitch to use social media for public health,  published on Vector, the hospital's blog:

You just had a great meal at a restaurant. So you grab your phone and fire off a glowing review on Yelp.

Consider the opposite scenario: You just had a horrible meal at a restaurant. So you grab your phone and fire off a scathing review on Yelp.Now here’s one more: You had a great meal at a restaurant but woke up vomiting the next morning. Do you grab your phone and fire off a complaint on Yelp that your dinner made you sick... A report in Preventive Medicine, authored by John Brownstein, PhD, Elaine Nsoesie, PhD and Sheryl Kluberg, MSc, judges Yelp’s usefulness as a food poisoning surveillance tool. Their efforts are part of a growing trend among public health researchers of trying to supplement traditional foodborne illness reporting with what we, the people, say on social media. It’s estimated that some 48 million Americans get food poisoning every year, but that number is likely far off the mark. “Foodborne illness is under-reported, under-documented and hard to get at,” says Brownstein, who co-founded the HealthMap epidemic tracking tool and who also has a data grant from Twitter focused on foodborne illness. Part of the problem is that food poisoning sufferers may stay out of work or school but aren’t sick enough to visit a doctor or hospital. It’s those medical interactions, though, that would normally trigger reports to and inspections by local public health authorities.

Brownstein and his colleagues conducted a little experiment to test their theory:

...Brownstein, Kluberg and Nsoesie used a sample data set from Yelp—5,824 restaurant reviews from 29 localities between 2005 and 2012—to identify and characterize possible food poisoning events. In particular, they wanted to see if the foods implicated in disease reports made sense, given the known common sources of foodborne illness (dairy, meat, fish, etc.). The categories of foods people blamed on Yelp did match data from the U.S. Center for Disease Control and Prevention’s (CDC’s) FOOD (Foodborne Outbreak Online Database) system very closely. For instance, 16 percent of the Yelp complaints mentioned seafood, compared to 12 percent of reports in FOOD. Similarly, meat or poultry stood out in 32 and 33 percent of Yelp complains and FOOD reports, respectively. What surprised the team, though, was the overall number of people who announced on Yelp that they’d gotten sick after eating out. Nearly 10 percent of the restaurant reviews in their data set mentioned a food-related illness.

And here's the bottom line, from the abstract:

Based on observations in this study and the increased usage of social media, we posit that online illness reports could complement traditional surveillance systems by providing near real-time information on foodborne illnesses, implicated foods and locations.

And now, Brownstein tells me via email, the group has launched a prototype system live and is "in the middle of doing testing with public health. So it’s rolling out over the next few months."