CDC Influenza Even the CDC has an app these days. Download it and you'll remain disease free. Well, maybe. Keep an eye on the flu with the "influenza activity and surveillance" section. Worried about the shot? The vaccination tab explains everything in a pinch. And do your research before taking any pills. The "antiviral drugs" tab will give you the 411. The free app is compatible with iPhone, iPod touch, and iPad, but requires iOS 4.0 or later.