The previously observed differentiated regulation of DDC, ACE2, dACE2 and EPO gene expression in the in vitro infection studies and the nasopharyngeal swab samples of SARS-CoV-2 infected subjects with mild or no symptoms, could be related to an antiviral response of the host in an attempt to restrict the propagation of SARS-CoV-2. This evidence concerns the gene EPO and infection.