IFNAR1 and infection: Infected IFNAR1 mAb treated mice showed enhanced weight loss, lung infiltration in perivascular and alveolar sites with macrophage accumulation. Neutralizing mAb against the SARS-CoV-2 receptor-binding domain ameliorated weight loss and virus burden in lungs of transduced, IFNAR1 mAb-treated mice Non-lethal infection with virus being undetectable by day 14 post infection.