PSMD1 and COVID-19: The current study aims to investigate the seroprevalence of serum antibodies against SARS-CoV-2 in the general population before the emergence of the virus and during the early phase of the COVID-19 pandemic, using an ELISA designed to screen IgG antibodies directed against viral S1-glycoprotein receptor-binding domain (S1-RBD) protein antigen.