I have long thought that “isolating” in your home or in a nursing home was probably the best way to guarantee that not only did you get it, you got a really bad case of it.
Everything depends on the viral load. A light load (from casual contact of some kind) is enough to trigger the immune system to fight back and it is usually successful at that point. But being in an enclosed place, breathing the same virus-laden air for days on end, and in other words giving yourself a serious, concentrated dose of virus, is the thing that totally swamps the immune system, especially in an older or weaker person.
I noticed in Italy, too, that it was elderly couples locked into their homes or nursing home patients, locked into their wards, who seemed to get the sickest and have the highest rate of fatalities.
Yes. And if you have to be inside, open the widows and gets lots of air changes through your house. Don’t let the virus get concentrated anywhere.