Fig. 2

SARS-CoV-2 spike S1-specific IgG subclasses in older adults following repeated mRNA vaccinations. SARS-CoV-2 spike S1-specific IgG1, IgG2, IgG3 and IgG4 concentrations (AU/mL) following mRNA vaccination were measured in serum by multiplex immunoassay for older adults (n = 50) up to one month after the fifth vaccination. Dotted lines indicate the cut-off for seropositivity. SARS-CoV-2-infected individuals (based on N seropositivity) are indicated with open circles. Differences between groups were assessed using a non-parametric Wilcoxon signed rank test with Bonferroni’s correction for multiple testing. ** P < 0.01, **** P < 0.0001. AU, arbitrary units; N, nucleoprotein