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).