2.2 SARS-CoV-2 antibodies test
The titer of anti-SARS-CoV-2 IgG, IgM, and IgA were measured by enzyme-linked immunosorbent assay (ELISA) (WANTAI BioPharm, China) and magnetic chemiluminescence enzyme immunoassay (MCLIA) (Bioscience based on indirect immunoassay, Tianjin, China) as described previously.3 Neutralizing antibodies (NAb) against S-RBD of WT, Delta, BA.1, BA.2, and BA.4/5 strains (Supplemental Figure 3), were measured using competitive enzyme-linked immunosorbent assay (cELISA) (Vazyme, China) (Supplementary Methods).