How can you claim that when noone who has caught Covid-1 has lived 17 years yet? only 8,000 Sars2003 cases worldwide - that’s not a lot of people with ‘natural immunity’. Does natural immunity against Covid-1 mean natural immunity against Covid-Delta or Lambda? or all coronaviruses?
https://www.cdc.gov/media/presskits/sars/cases.htm
https://en.wikipedia.org/wiki/2002%E2%80%932004_SARS_outbreak
How can you claim that when noone who has caught Covid-1 has lived 17 years yet? only 8,000 Sars2003 cases worldwide - that’s not a lot of people with ‘natural immunity’. Does natural immunity against Covid-1 mean natural immunity against Covid-Delta or Lambda? or all coronaviruses?
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SARS was more than 17 years ago. And it is very similar to this virus.
The 80% estimate comes from a study that showed that the impact differed depending upon how similar to CV19 the prior exposure was.
The study included review of blood that was taken before the CV19 outbreak. It showed that prior coronavirus(not just SARS) also had some demonstrated immunity. The T cell and neutralizing antibodies were found to be more important than the binding antibodies.
The vaccines are heavy on the binding and not so good on the other categories. That might have something to do with why the vaccine is losing effectiveness faster than anticipated.
So far, it’s looking like the traditional inactivated virus vaccine method would have been a better way to go.