Facebook could be used to alert you when you are at risk of contracting herpes or HIV. More than just a privacy advocate’s nightmare, researchers are already exploring the power of social networks to predict and prevent the spread of STIs. As reported in Salon, researchers such as Peter Leone at the University of North Carolina’s Center for Infectious Diseases, are helping the fight against STIs go viral. Real-world social networks are already known to be strong predictors of contracting STIs. Friends from the same social circles often have sex with the same people or engage in similar risky behaviors. In one case, says Leone, they could connect 80 percent of cases during a syphilis outbreak in North Carolina to the social networks of people infected—“who they hung out with, who they knew.” His team has extended this concept to the virtual world of Facebook. When someone tests positive for HIV, his team contacts that person’s sexual partners and friends—sometimes through Facebook—to let them know they might be at risk. Contact through Facebook is done only with the infected person’s permission. Traditional efforts to reduce the spread of STI often involve contacting at-risk populations or sexual partners of those who are infected. The social network approach widens the circle to include more people who might be missed. This technique has already been used to predict people’s risk of catching the flu. An app looks at keywords in the status updates of your friends and alerts you when you are in danger of getting sick. This type of app doesn’t exist yet for STIs. And it may never, largely due to privacy concerns and people being less willing to share updates about their herpes blister on Facebook. Social networks like Facebook, though, can be used to educate people and spark conversations about STI risks and testing. This is already happening with MTV’s “GYT: Get Yourself Tested” campaign. Uses can earn a badge from Foursquare when they check in while getting tested for an STI.