"I believed I might have had Covid-19 in January of 2020, even though I tested negative for antibodies several months later. As it turns out my later antibody testing (negative) was correct and not a defective test; whatever I had in January of 2020 it was not Covid-19."

I can't tell you, the amount of folks I know (Myself included) that had heavy travel for convention work around that time. MANY of them came down with "Something" in Jan / Feb that was not a flu, not a cold, not food poisoning.

I have no doubts, there was an earlier version of this thing floating around and what "They" said was the 1st wave, was really a mutation wave.