Well then we should ban all situations that involve any proximity to people, like supermarkets, off track betting etc. If you fear that then how can sitting or standing near anyone be safe? But if you fear hand to mouth then my point is correct. You don’t breathe when you open your mouth to eat.
Don't be ridiculous. My point is about minimizing risk, not "fear". Analyze the sequence of the ritual. You approach the priest. He picks up a Host, holds it in front of your face, and says "the Body of Christ". Now, the way I learned it is that the communicant at that exact point says "Amen". Try saying "Amen" without exhaling. Which happens at the worst possible time for mouth-to-hand bacterial transmission. This, by the way, happens with both "on the tongue" AND "in the hand".
"If" one does NOT say "Amen", then the risk of mouth-to-hand transmission drops essentially to zero for "in-the-hand", but not for "on the tongue".