(A) Viral RNA levels harvested from the apical surfaces of ALI cultures infected with indicated SARS-CoV-2 variants 1 h post-treatment with IFNs (α2, β, and γ at 0.5, 5, 50, and 500 IU/ml or λ1 at 1, 10, and 100 ng/ml) quantified by qRT–PCR at 5 d postinfection (MOI 0.5). Individual donors are indicated. (B) Viral RNA levels harvested from the apical surfaces of ALI cultures infected with SARS-CoV-2 omicron BA.1 (MOI 0.5) quantified by qRT–PCR at 2 h (wash CTRL), and 3- and 5-d postinfection. Individual donors are indicated.