PSMD1 and COVID-19: Among study participants without prior SARS-CoV-2 infection reflected by the absence of anti-NC-SARS-CoV-2 antibodies, the median anti-S1-RBD-SARS-CoV-2 antibody titer significantly increased between those who received only one (median AU/mL [IQR]: 564 [24–3070]) to those who received two (median AU/mL [IQR]: 1663 [1094–3060]), three (median AU/mL [IQR]: 13,856 [8,635–22,705]) or four (median AU/mL [IQR]: 25,000 [25,000–25,000]) COVID-19 vaccine doses (p < 0.0001) (Figure 1).