ACE2 and infection: Our study results clearly demonstrated that in addition to block the entry and subsequent infection of host cells by the SARS‐CoV‐2 pseudoviruses as well as the SARS‐CoV‐2 clinical isolates, the ACE2‐Fc (18–615 A.A.)fusion protein is very stable in plasma up to 10 days and also preserve its peptidase activity to exert its regulator effects on immune responses (Figs 6 and 7).