Want To Know Who Gave You The Flu? There’s An App For That! If you’ve got the flu, finding out who gave it to you might make you feel better. “Help, I Have The Flu,” a new Facebook app that analyzes your friends via keywords, posts and check-ins to find who has the flu – so you can track them down and let them know what they’ve done to you, or avoid them completely for a few days. The app also lets you send a message to your guilty friends that advise them that they won’t be enjoying your company for a little bit.