ACE2 and infection: As we recognize that immunities generated by vaccination versus infection are known to produce antibodies targeting different parts of S protein28 and that the protection against variants based on vaccination and/or previous infection is variable, we tested the same patient samples used to validate β10-(S)WT/ β9-ACE2-Fc, along with an additional set of infected patients (n = 35), for the samples’ neutralization efficacies towards different variants of concern.