FIG. 2. The serial changes of (A) anti-RBD IgG binding antibody and (B) neutralizing antibody levels before (baseline) and after the first (post-dose 1) and second (post-dose 2) vaccination of COVID-19 mRNA vaccines in the control, adjuvant, and palliative groups. The levels are on the logarithmic scale and indicated as a scatter dot-plot with median and interquartile ranges. The dotted lines are the threshold for positivity suggested by the manufacturers in conversion to the World Health Organization’s standard units (A: 7.1 BAU/mL, B: 28.4 IU/mL). ^*p<0.05; ^**p<0.01; ^***p<0.001.