Cruise ship with 3711 passengers quarantined off the coast of Japan for ~ 2 weeks. Only 19%+ infected(712). All passengers isolated in their rooms.
Odd circumstances, there were multiple instances where one member of a cabin pair (husband and wife, usually) got seriously ill while the other did not only not get ill they did not test positive either. Very similar to what you referenced regarding family members.
It implied there was either partial or pre-existing immunity. Death count reporting varied from 7 to 14 all older with comorbidities.
“Diamond Princess proved that the claim, which continues to be made today, that (1) this virus is extremely deadly and (2) there is zero cross or innate immunity were both false. It is not possible for a very transmissible respiratory virus to infect one person in a quarantined cabin of two people, while the other does not get sick at all unless either (1) the second person is already immune or (2) the second person gets it but has no symptoms at all and recovers before being tested, and thus tests negative.”
https://market-ticker.org/cgi-ticker/akcs-www?singlepost=3537309
This was early 2020
Thanks for this link.
My wife reminded me that one of my female siblings and some 0f her off spring and female grandkids and this sibling never got a serious Covid infection. Yet, their spouses often got hit hard.
There is a joker in this group of people, (young previously healthy 18~50+ women) seem prone to the long term Covid.