First off, let me just say I have no problem with people smoking/vaping. I don't myself but people are welcome to.
The other day as I was walking along, the two people in front of me exhaled massive clouds of vapour which I walked straight into.
It only then occurred to me that I was breathing in warm damp vapour almost directly from someone else's lungs.
AIBU to think that this is potentially a very easy way to spread infection?
I hope I don't sound precious - I'm more curious as to the 'science' behind it.