Representative pre-F and post-F probe-binding profiles from a single participant vaccinated with DS-Cav1 (pre-F, N = 30) or MEDI7510 (post-F, N = 30) at W0 and W1 are shown. Fluorescently labeled pre-F or post-F probes were used to separate class-switched memory B cells into three compartments (pre-F-preferring, dual-binding, or post-F-preferring). IgG+ (A) representative binding profile and (B) quantification of probe-binding B cells are shown. IgA+ (C) representative binding profile and (D) quantification of probe-binding B cells are shown. For all graphs, asterisks denote the P-value, with ****P < 0.0001, ***P = 0.0001 to 0.001, **P = 0.001 to 0.01, *P = 0.01 to 0.05, and ns = not significant as determined using Brown-Forsythe and Welch ANOVA tests (B) or Kruskal-Wallis tests (D). Red circles denote participants who received DS-Cav1, blue squares denote participants who received MEDI7510.