Figure 1.

Seroprevalence of ZIKV-reactive IgG in cord blood. ZIKV IgG (A) and ZIKV EDIII (B) ELISA were performed on cord blood plasma diluted 1:200 from Cohort 1 (n = 104) and Cohort 2 (n = 135). The cutoff for positivity was determined on each plate by running negative control plasma. The percent seropositivity for each assay is shown beneath the cohort names, and the geometric mean (GM) of OD for positive samples is shown beneath that. (C) The OD value from the ZIKV EDIII ELISA for available paired samples (n = 102) from mother peripheral blood and cord blood are graphed in a scatter plot to assess the efficiency of ZIKV-reactive IgG transfer across the placenta. Pearson correlation analysis was performed, and the R² and p values are included in the upper left corner of each graph. ns, not significant; ****, p < 0.0001 according to an unpaired Student’s t-test comparing differences between GM of Cohort 1 vs. Cohort 2.