IFNA2 and COVID-19: In their original publication, Bastard et al. used an IFN-α concentration of 10 ng/mL for 1/10 diluted plasma, which they recently repeated in an assay with a lower IFN-α concentration of 100 pg/mL (corresponding to 1 ng/mL in circulating blood), resulting in a detection rate of neutralizing IFN-α Abs of 13.6% in critically ill patients and 6.8% of severely ill COVID-19 cases [22].