Yes I did, you must have missed it in the parent comments.
https://www.publichealth.columbia.edu/public-health-now/news...
From article: "A new study published in the journal Nature estimates that 103 million Americans, or 31 percent of the U.S. population, had been infected with SARS-CoV-2 by the end of 2020"
Over 100 million! Past covid and therefore natural immunity.
Just because someone suffered an infection, it doesn't mean they're now naturally immune. That immunity might have worn off, or their illness may not have been severe enough to provoke an immune response that confers as much protection as one of the vaccines do.
I would love to read a study that shows natural, extended immunity in everyone (or even just many or most people) who has been previously infected, but I don't think that study exists, and it's telling that you haven't linked to one.
https://www.bloomberg.com/news/articles/2021-08-27/previous-...
https://www.science.org/content/article/having-sars-cov-2-on...
From science.org article: "The natural immune protection that develops after a SARS-CoV-2 infection offers considerably more of a shield against the Delta variant of the pandemic coronavirus than two doses of the Pfizer-BioNTech vaccine, according to a large Israeli study that some scientists wish came with a “Don’t try this at home” label."
Also, the evidence says that the antibodies are slated to last a lifetime.
Just because someone suffered an infection, it doesn't mean they're now naturally immune. That immunity might have worn off, or their illness may not have been severe enough to provoke an immune response that confers as much protection as one of the vaccines do.
I would love to read a study that shows natural, extended immunity in everyone (or even just many or most people) who has been previously infected, but I don't think that study exists, and it's telling that you haven't linked to one.