Fig. 1

Antibody response to SARS-CoV-2 mRNA vaccine. A Multiplex bead-based antibody binding assay that measures the IgG antibody response to 4 SARS-CoV-2 viral antigens (S1, S2, RBD, and NP). Median Fluorescent Intensity (MFI) is shown and background well subtraction has been used to remove nonspecific signal. Each dot represents an individual at baseline before vaccine (week 0), 3 weeks after the first dose of vaccine (week 3) or 4 weeks after the second dose (week 7). Bars represent the group median. The number of individuals in each group are shown below the graphs. Individuals with a previous history of SARS-CoV-2 infection (seropositive; blue), no previous history of infection (seronegative; red), and individuals with possible undiagnosed infection (green). The dashed line indicates a threshold determined by the sum of the mean and standard deviation for the negative control (beads without antigen). B Neutralization antibody proxy assay that determines the level of antibodies that block the RBD-ACE2 receptor-binding expressed as the percentage of binding that was blocked relative to control with no plasma (representing maximum binding). The assay threshold for positivity was 30%. Each point represents an individual at baseline before the vaccine, 3 weeks after the first dose of vaccine (week 3) or 4 weeks after the second dose (week 7). Bars represent the group median. The number of individuals in each group are shown below the graphs. Individuals with a previous history of SARS-CoV-2 infection (seropositive; blue), no previous history of infection (seronegative; red), and individuals with possible undiagnosed infection (green). Statistical tests for significant differences between groups were unpaired, two-tailed Wilcoxon-Mann-Whitney test with a significant threshold of P < 0.05