Fig 1: Immunogenicity of prototype-Beta chimeric vaccine in rhesus macaquesTwenty-four rhesus macaques (see Table S1) were immunized with 3 doses of prototype-Beta chimeric RBD-dimer vaccine or sham (n = 12), 21 days apart. Serum samples were collected according to the study schedule shown in Figure S5B.(A) Endpoint titer of antigen-binding IgG.(B) 50% neutralization titer of pseudotyped virus (prototype, Alpha, Beta, Delta, and Omicron) in serum.(C) 50% neutralization titer of authentic SARS-CoV-2 (prototype, Alpha, Beta, and Delta).(D) 50% neutralization titer of authentic SARS-CoV-2 (prototype, Beta and Omicron). The values shown in (A)–(D) are the GMT ± 95% confidence interval (CI).(E) Summed IFN-?, IL-2 and IL-4 ELISPOT responses in PBMCs collected at day 6 after the third dose toward peptides spanning SARS-CoV-2 RBD. The values are means ± SEM. p values were analyzed with two-tailed Mann-Whitney test. (**p < 0.01; ***p <0.001; ****p < 0.0001).