Fig. 4

Comparison of SARS-CoV-2 spike S1-specific IgG subclasses following mRNA vaccination between younger and older adults. 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 younger (n = 64) and older (n = 50) adults up to one month after the third 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 unpaired Wilcoxon signed rank test with Bonferroni’s correction for multiple testing. **** P < 0.0001. AU, arbitrary units; N, nucleoprotein; ns, not significant