IFNA1 and COVID-19: People with severe COVID-19, however, may display reduced or delayed IFN responses, which could be due to genetic factors, antibodies that neutralize the IFN, or a decrease in the number of plasmacytoid dendritic cells that produce TLR7, a toll-like receptor that recognizes single-stranded viral ribonucleic acids and initiates IFN responses [29,30].