PSMD1 and infection: Participants were not previously vaccinated with SARS‐CoV‐2 vaccines, and only 7 individuals showed Spike‐specific S1 IgG concentration above the cut‐off level for seropositivity (10 BAU/mL) indicative of previous infection; therefore, instead of maxRBA, Day 28 antibody levels were used for antibody response quartiles.