FCGR3B and COVID-19: Although each individual exhibited a unique overall isotype/subclass/FcR-binding profile, some distinct differences in Fc profiles were noticeable across the cases and controls, including reduced SARS-CoV-2-specific antibody FcγR2B binding in blocks of vaccinees who did not develop COVID-19 and a uniformly lower-level, SARS-CoV-2-specific antibody FcγR3B binding in vaccinees who later developed COVID-19.