The FDA document, dated May 19, 2021, is titled: “FDA In Brief: FDA Advises Against Use of SARS-CoV-2 Antibody Test Results to Evaluate Immunity or Protection From COVID-19, Including After Vaccination”. [1] [1a]
Digging a little deeper in the document, we have a statement referring to the COVID vaccine:
“The authorized vaccines for prevention of COVID-19 induce antibodies to specific viral protein targets; post-vaccination antibody test results will be negative in individuals without a history of previous natural infection if the test used does not detect the type of antibodies induced by the vaccine.”
“Is this blog (which seems to deny the SARS-CoV-2 virus exists) protected against posting more than 85 words:”
No it was my choice. I do not like copying full stories.
That's an unnecessarily complicated sentence, but it seems natural infection reliably produces antibodies where the authorized (not approved, as if responsibility ever mattered) vaxxines, even if they produce any antibodies, will not show positive test results for antibodies.
Corollary: Post vaxxine "breakthrough cases," while sounding extraordinary, are commonplace, just as post-vaxxine negative antibody test results would suggest. Therefore, our test results show that vaxxines don't really work. There is protection with cases of a history of natural infection, however.