To establish whether partial replacement of the ORF3a coding sequence with those of the fluorophores increased the IFN sensitivity of SARS-CoV-2, AAT and VTN cells were dosed with different amounts of IFN-α prior to infection with rSARS-CoV-2, rSARS-CoV-2-Δ3a-mNG and rSARS-CoV-2-Δ3a-mS. Here, IFNA1 is linked to infection.