CCR5 and COVID-19: Thus, in regard to the clinical course of COVID-19, the roles of CCR5 (1) within the oral–pharyngeal immune system as the first line of antiviral immune defense and (2) as a critical receptor governing adaptively induced T-cell memory provide a compelling immune-mechanistic rationale for the putative association of the delta32 near-loss-of-function mutation of CCR5 with altered susceptibility to SARS-CoV-2 infection and COVID-19 morbidity [6–9].