Figure 4

Heatmaps representing the log mean fold change values of spike-specific and total serum IgG subclasses in three follow-up mRNA vaccinated groups between two sampling time points after booster vaccination. The fold changes of spike-specific and total serum IgG subclasses and the proportions of each spike-specific to total serum IgG levels were visualized in heatmaps by the logarithmic values of mean ratios between the second and the first sampling time points. Decreasing trends are shown between 0 and (− 1) and increasing trends were plotted between 0 and 1. The constant level (no change) is indicated as 0.