14 minute video
https://www.youtube.com/watch?v=aU7uBmLUiiY
Overall, more than 90% of current blood donors have either been infected with covid or vaccinated against it, said Dr. Michael Busch, director of the Vitalant Research Institute, who is monitoring antibody levels in samples from the U.S. blood supply.
Less than 10% of the blood we collect does not have antibodies, Busch noted.
https://archive.is/9gSTQ#selection-671.256-671.501
if you take a vaccine, and then subsequently DO NOT get an infection,
that is considered irrefutable evidence that vaccines work.
but if you get infected once, and subsequently DO NOT get infected again,
thats considered an anecdotal correlation