In another thread there was a screen capture of some “top secret” guy talking about how this was weaponized. I hope it was just a spoof.
But it said it starts out as a flu, and in a couple weeks the real bad virus kicks in. Lungs burst and cough out blood and die.
Two of the images I saw with the bodies on the ground had blood by the head. Perhaps from falling, but perhaps from coughing up blood. (Or, hopefully - those clips are just from some budget horror flick!)