We showed that all of the K18-hACE2 mice i.n. immunised with one dose (2 × 104 or 2 × 103 pfu) of CoV-2-CNUHV03-CA22 °C were completely protected from the infection of wild-type SARS-CoV-2 (CoV-2-KCDC03) and did not show any loss of body weight, or detection of virus in different tissues (nasal turbinates, brain, lungs, kidneys) in terms of the log10TCID50 values or as determined by RT-qPCR. The gene discussed is KRT18; the disease is infection.