Figure 1. SARS-CoV-2 Spike Receptor-Binding Domain (RBD)–Specific Antibody Levels After Vaccination and Breakthrough Infection.

Enzyme-linked immunosorbent assay measurement of serum dilution titers with a 50% effective concentration (EC₅₀) of SARS-CoV-2 spike RBD-binding antibodies. The dotted lines indicate the assay limits of detection. Two-tailed P values were determined using the Wilcoxon matched-pairs signed rank test with the Holm-Šídák multiple comparison correction. Box plots were generated using the Tukey method. The large box displays the median and IQR. The error bars indicate 1.5 times the IQR or the furthest outlier, whichever is closer to the median. All individual data points are displayed as filled circles.