The auto-Abs detected were of a similar nature to those observed in patients with critical COVID-19 pneumonia, with most patients having auto-Abs neutralizing high concentrations of IFN-α2 (∼70% in the influenza cohort and ∼60% in the COVID-19 cohort), a minority of patients having auto-Abs against IFN-ω only, and even fewer auto-Abs against IFN-β only (Table 1). Here, IFNA2 is linked to influenza.