While we were able to confirm the cell-to-cell infection of SARS-CoV-2 using the authentic WA-1 strain, syncytia formation was not evident in most cases, except when Vero-ACE2-TMPRRS2-mTomato and Vero-ACE2-TMPRRS2 cells were used as donor and target cells, respectively, because of the high level expressions of both ACE2 and TMPRSS2. The gene discussed is TMPRSS2; the disease is infection.