PSMD1 and COVID-19: Additionally, we observed a significantly higher amount of anti-RBD IgG in older men, and it was previously shown in a preprint article where the authors suggested that being male, an older adult, and being hospitalized with COVID-19 were each associated with having greater neutralizing antibody titers and IgGs against the S1-domain, the S1-RBD fragment, or the full spike protein [26].