Figure 2.

Anti-RBD IgG antibody concentrations

(A) Anti-RBD IgG antibody concentrations following the third and fourth vaccine doses in the vaccine group and third vaccine dose in the control group. P values show unadjusted comparisons between the vaccine group and control group, and between third and fourth vaccine dose in the vaccine group. (B) Anti-RBD IgG antibody concentrations following a fourth vaccine dose in the vaccine group and COVID-19 after three vaccine doses in the hybrid group. P values show unadjusted comparisons between the vaccine types (BNT162b2 or mRNA-1273) in the vaccine group, and between the hybrid group and the vaccine group. Violin plot of probability densities, smoothed by a kernel density estimator. Points denote participants, and solid black lines show group medians. RBD=receptor binding domain.