Figure 7. The anti-spike IgG optical density (OD) ratio across different age groups.

The median spike OD ratio for each age group was 0.088, 0.156, 0.219, 0.198 and 0.323 for >0-20, >20-30, >30-40, >40-50 and >50, respectively. The total number of samples in each age group is indicated. The OD ratios between each group were statistically compared using a Wilcoxon test. The p-values are shown only for the groups with a significant difference.