Elon Musk shared a first hand experience that is very enlightening. 4-tests with same person back to back, same test method, same machine, same nurse. Terrifically simple controls. Results 2 positive and 2 negative. Which is right? Flip a coin, 50:50, 50% false positive or false negative?
This 50% false, is actually better than I expected and is the kind of crappy data being fed into the “case” numbers that most everyone is wringing their hands over and triggering the quarantine and contact tracing mania. I haven’t kept up with current false positive performance of the antibody tests but in the spring they were documented to have a 90% false positive rate.
BTW, the persons replying to Elon’s tweet are ignorant jerks for the most part. I suspect it was simply to detract from the in your face documentation of the COVID testing game being played on us. Elon, very brilliantly played!
Infection to some extent must occur for production of antibodies. Antibodies are tailored specific to a viral stimulus. A virus can cause an antibody generation event without resulting in apparent illness.
A virus must be present over an individual’s specific threshold, so as to multiply faster than the body mounts a defense, and result in presentation of disease. Everyone’s response is different due to genetics, age, nutrition, and prior exposure to other pathogens.