Not the nicotine but something in the tar perhaps? However it doesn’t negate that those with COPD who may not be currently smoking or have quit even years ago are going to be very high risk for dying of Covid and the pneumonias that stem from it. The lung damage from aveoli loss from previous copd makes covid a real threat.
I’m waiting for data on pot smoking, if the tars from that also might have a protective quality!
It might be ironic to discover that getting stoned from pot once a day with a large number of people doing it will squash the pandemic. (yeah I know,,,not plausible, just funny to think about. I’m not a pot advocate)
I have a relative in his 70s diagnosed recently with COPD and he’s never been a smoker. And his profession for most of his life was as a butcher - not where I’d expect air conditions to be contributors to COPD.