Not an immunologist and it has been 25 years since studying the immune system in school, but I think the antibodies are present for a short while. The lymphocytes “remember” a virus for a long time.
When an antigen is detected (antigens are the binding sites for antibodies) lymphocytes undergo mitosis, producing more cells which express antibodies to the antigen.
There is a test called T-Detect which determines if one has ever been exposed:
This test was cleared by the FDA last March under EUA.
Maybe if someone can give more technical details that would help.
I’m ordering the test tomorrow and scheduling the blood draw locally.
I’ll post a new thread on both it and the results of my infiltration behind enemy lines (pretending to be interested in getting the ‘vaccine’ next week).