I have severe COPD, so I am aware that I must try, at all cost, to avoid an exacerbation. Some years ago I saw a TV programme which showed various experiments of how to avoid getting 'germs.' One of the tests they did was one group of people greeting each other by shaking hands, and the other group doubling kissing on the cheeks as the French do. The ones who transferred the most germs were the hand-shakers, and the kissers transferred less.
I made note of this, as I live in France, and they are always wanting to give you a "Bisou" a double kiss, even when they have a cold. Now I put my hand up and try to explain that I must not get germs, and also, I take their hand, then, as I carry anti-bacterial soap with me, I use it all the time. It works!!!