Simplified approach to COVID natural and pre-existing immunity using the Petri-Dishes that Boats Are….
Dr. Fakeci, let’s take a look at some updates and just consider the number of symptomatic, AKA real cases. First, the Diamond Princess:
The researchers examined data on 197 people with symptoms on the ship, using records published by Japanese authorities. There was a total of 712 confirmed cases among passengers and crew, around half of whom were asymptomatic at the time of testing, so the data are limited. [https://www.bmj.Com/content/369/bmj.m1632 ]
So, of the 3700 passengers and crew, 712 cases eventually were found or 19.2%. Since only half showed symptoms, that means that about 90% were immune.
Second, The Theodore Roosevelt with a crew of 4,779:
Over the course of the outbreak, 1271 crew members (26.6% of the crew) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by rRT-PCR testing, and more than 1000 infections were identified within 5 weeks after the first laboratory-confirmed infection. An additional 60 crew members had suspected Covid-19 (i.e., illness that met Council of State and Territorial Epidemiologists clinical criteria for Covid-19 without a positive test result). Among the crew members with laboratory-confirmed infection, 76.9% (978 of 1271) had no symptoms at the time that they tested positive and 55.0% had symptoms develop at any time during the clinical course. Among the 1331 crew members with suspected or confirmed Covid-19, 23 (1.7%) were hospitalized, 4 (0.3%) received intensive care, and 1 died. [ https://www.nejm.Org/doi/full/10.1056/NEJMoa2019375 ]
Picking the numbers of interest out of all that we see that about 25% tested positive, but just about half were asymptomatic, so 88% were immune. That’s pretty good agreement with the Diamond Princess.