The goal of the current study was to assess the association of COVID-19 clinical courses controlled by patients’ adaptive immune responses without progression to severe disease with patients’ Human Leukocyte Antigen (HLA) genetics, AB0 blood group antigens, and the presence or absence of near-loss-of-function delta 32 deletion mutant of the C–C chemokine receptor type 5 (CCR5). This evidence concerns the gene CCR5 and COVID-19.