I read that article, and basically said “Oh sh—.”
I wonder if the difference between mild and severe cases is that for some reason, in most healthy people the virus doesn’t really do well in the lower lung, but is still highly infectious - something like a typical “common cold” but without severe nasal congestion and sore throat. In less healthy people, or those with weak immune systems, elderly, etc., maybe COVID-19 for some reason finds the lower lung area the weak spot - with a vengeance.
Now, this is HIGHLY anecdotal experience, but in my own case I’ve noticed that as I got past 60 or so, I’ve tended to not get those wicked head colds I used to. (They really ramped up on me during several years when monthly air travel for my employer and other factors increased my exposures.) But, now the colds are mild initially - very slight head cold symptoms - and transition right into my lungs and stay for a month or two. These chest colds are not “severe”, tho’ they can slow me down somewhat, and I don’t seem to transmit them to my wife or daughter.
I figure this could be different viruses running around as time goes by, or, my response to the same virus or viruses has “evolved”.
we change as we get older, that’s the truth. Like you I don’t get those massive head colds, but for me, they’ve been replaced by allergy congestion and runny nose (ah...maybe that will keep the virus washed out ! wishful thinking.) And I do get chest colds that last more than a few weeks, too. Maybe it’s different viruses. It’s been said you’re supposed to be immune to every one you survive. And there are a whole lot more of them than us!