Figure 5.

Binding profile of antibodies from individuals of the “breakthrough infection” group against Omicron BA.1 antigens. Immunoglobulin (Ig) G, IgM, and IgA antibody levels against BA.1 spike and BA.1 receptor-binding domain (RBD) antigens of Omicron BA.1, expressed as area under the curve (AUC) (n = 24). BA.1 refers to the sequence of the first isolate of the Omicron lineage. The limit of detection is indicated by the horizontal dotted line. A parametric paired t test was performed to compare prebreakthrough (Pre) and postbreakthrough (Post) infection responses. The average fold change occurring with breakthrough infection is indicated for each Pre-Post pair, represented by dots. *P < .03; **P < .002. Each symbol represents a single participant; bars, geometric mean; and error bars, geometric standard deviations.