[omginternets]

>The coffee filters people are wearing over their face will do close to nothing

I'm not an expert, but I believe this is not quite accurate. As I understand it, even a piece of cloth helps prevent the spread of the virus to others. The mechanism is that the virus exits your nose/mouth in the form of macroscopic droplets that later break down into microscopic droplets a few inches from your face. A bandanna will catch the big droplets before they split apart.