Wild type mice (BALB/c, C57BL/6), immunodeficient mice (SCID), chimeric mouse expressing human angiotensin-converting enzyme 2 (hACE2), and the RNA-dependent RNA polymerase (SARS1/SARS2-RdRp) were evaluated as models of COVID-19 (Table 3). The gene discussed is SARS1; the disease is COVID-19.