Fig. 2.

Anti-spike IgG levels at 5–6 months following the second dose of the BNT162b2 vaccine. (A) Kinetics of anti-spike IgG levels of each participant as measured by the Sysmex test. The median values of each data point are displayed as solid black circles connected with solid black lines. Shaded areas in blue indicate the 25%–75% percentile. (B) Correlation between age and S-IgG levels in the December survey as measured with the Sysmex test. (C) Comparison of antibody levels among the different age groups and between the sexes. Data are expressed as box plots: middle line, median; box edges, 25th–75th centile.