ACE2 and infection: We report that the BA.1, BA.2, BA.2.12.1, and BA.4/5 Omicron sublineages, which account for >99% of all infections worldwide over the first half of 2022, have increased ACE2 binding affinity, have decreased fusogenicity, and markedly evade neutralizing antibody responses relative to the Wuhan-Hu-1 and Delta strains (3).