Our examinations strongly suggested that patients experiencing severe/critical symptoms and longer hospitalization had significantly greater neutralizing activity and SARS-CoV-2-S1-binding antibody amounts than those having mild/moderate symptoms and shorter hospitalization periods, suggesting that the longer exposure of COVID-19 patients to greater amounts of SARS-CoV-2 elicits greater immune response to the virus, producing greater neutralization activity and SARS-CoV-2-S1-binding antibody amounts. This evidence concerns the gene PSMD1 and COVID-19.