That also seems wildly optimistic. 80% seems like a more reasonable assumption than 20%.
Also - 99.9% of those patients (pulled out of a hat) wouldn't have access to health care because the capacity was already overwhelmed, so the death rate will jump markedly.
Because 712 out of the 3711 passengers and crew were infected, and 713÷3713 ≈ 19.2%. So that gives us some sort of vague idea how much of the population from which the ship was drawn will become infected if exposed.
That also seems wildly optimistic. 80% seems like a more reasonable assumption than 20%.
Also - 99.9% of those patients (pulled out of a hat) wouldn't have access to health care because the capacity was already overwhelmed, so the death rate will jump markedly.