@metal-brain said
You need to clarify #3. Were you drinking when you wrote that?
Of course I was drinking. 8 cups of water a day, they say. That takes a lot of time.
Okay, I'll break it down:
1. There are lots of circulating coronaviruses, not just SARS-CoV-2.
2. They all produce antibodies in reaction when they infect someone
3. Antibodies produced against one coronavirus may not be all that different from those produced against another
4. The antibodies tests we have may not be able to 100% distinguish between antibodies to one coronavirus as opposed to another
Antibodies are not segregated tools only brought out against the specific virus they were produced to fight. There's lots of cross-immunity, where antibodies produced against one virus can fight other ones.