Figure 1.

Antibody binding response is significantly reduced for both BA.1 and BA.2. Binding response by preexisting antibodies generated through either infection or vaccination was measured with MULTICOV-AB (A) and RBDCoV-ACE2 (B) assays and Biolayer interferometry (C and D). A, Boxplot showing that immunoglobulin G binding is significantly reduced for both BA.1 and BA.2 as compared to other variants of concern (VOCs)/variants of interest (VOIs) for convalescent (n = 86) and vaccinated (n = 226) samples. Negative samples are included as controls (n = 15). B, Boxplot showing that ACE2 binding inhibition is significantly reduced for both BA.1 and BA.2 as compared to other VOCs/VOIs for both convalescent and vaccinated samples. Boxes represent the median with 25th and 75th percentiles; whiskers show the largest and smallest nonoutlier values. Outliers were determined by 1.5 interquartile range. C and D, Binding kinetics of receptor-binding domain (RBD)–specific antibodies from serum samples of convalescent and vaccinated individuals (both n = 5). Binding response (C) and dissociation constant (D) were determined by 1:1 fitting model of the individual serum samples between the different RBD variants. Median fold reductions for both (A) and (B) can be found as Supplementary Tables 1–3 and 5. Statistical differences between all variants was analyzed by Wilcoxon signed-rank test for both (A) and (B) and is available as Supplementary Tables 4 and 7. The response rate for (B) is available as Supplementary Table 6. Abbreviations: ACE2, angiotensin-converting enzyme 2; IgG, immunoglobulin G; Inf, infected; MFI, median fluorescence intensity; Neg, negative; RBD, receptor-binding domain; Vac, vaccinated; WT, wild-type.