ACE2 and infection: We indeed observed that SARS‐CoV‐2 reference strain infection of Calu‐3 cells could not be inhibited by recombinant mouse ACE2 but the Omicron infection was potently suppressed by both human and mouse recombinant ACE2 for the indicated MOIs, albeit at lower potency when using soluble mouse ACE2 (Appendix Fig 4).