IFNA2 and pneumonia: Remarkably, approximately 4%–8% of the general population aged over 70 years harbor autoantibodies (auto-Abs) neutralizing IFN-α/ω (31), which can underlie severe COVID-19 pneumonia (31, 32), MERS critical pneumonia (33), influenza critical pneumonia (34), West Nile virus encephalitis (35), and adverse reactions to the live attenuated yellow fever vaccine (36).