Health

the former especially remains viable for quite some time on inanimate surfaces which you then touch and self-contaminate mucus membranes of your eyes, nose, and mouth. Flu similarly but is a little less "hardy". So as easy as it is to make a little error--rubbing your eye, or nose with contaminated hands you just may have become infected. Eye protection (glasses) can help especially in crowded environments like planes.

So, you need to do more than mask. Hand washing is paramount. And eye protection may just clinch your avoidance especially around those sneezing/coughing.