The Receptor Binding Domain of SARS-CoV-2 Omicron Subvariants Targets Siglec-9 to Decrease Its Immunogenicity by Preventing Macrophage Phagocytosis

Using reverse mutagenesis, the authors found that a phenylalanine-to-serine mutation at position 375 in the spike protein of Omicron to revert it to the sequence found in Delta and other ancestral strains significantly enhanced the immunogenicity of Omicron vaccines.