Here's one of my theories. In much of Europe, we have much more human contact on a daily basis in subways, trains, busses, trams, group lunches with co-workers, working in an office and not from home, interacting at the market, etc. So we are exposed continuously to whatever is out there and have built up a bit more immunity. At this point we approach Covid the same way we approach getting any respiratory disease and don't test for COVID-19 but would see a MD if feverish. It could be bronchitis or pneumonia.
"It is unfortunate that so much of Europe missed the opportunity to fully appreciate how viruses like Covid are transmitted and to encourage prevention particularly in crowded areas such as transit. We know it’s not a virus to get again and again."
Actually Claire, I am so thankful to be living in a society that controlled exposure with the Pass Sanitaire, values human contact, and has given us the freedom to go back to living the way we did before the C-19 epidemic started. We missed no opportunities and see Covid as an event just like a cold, which, by the way began as a covid virus, too. People who need to shield from C-19 need to shield from flu and many other diseases. Some of us living in most of Europe need more precautions, some don't.
However, Americans who have not been exposed as much as we have do need to be more careful. People living in a car culture, not socializing as before, working from home, etc. do need to be careful when they set foot over here if they haven't built up the same immunity yet. Vaccines do some of the work; for us, human interaction is doing the rest.
I did catch a runny-nose, slight cough C-19 in the plane going to the US to visit last fall. A young American was ill in the seat in front of me, caught here in Europe. 8.5 hours of being bombarded by his virus and wearing only a surgical mask gave me the cough and runny nose.
So N95 in the plane and you decide how mask-free or not you can be.
My 2-centimes.