Fig. 2.

Levels of receptor binding domain (RBD)- and S-binding antibodies in vaccinees. (a) Comparison of anti-RBD antibodies titres in vaccinees after the second dose of the CovIran vaccine (intervention, n = 36) and nonvaccinated persons (placebo, n = 12). (b) Comparison of S-binding antibodies levels in the total vaccinees (intervention) and nonvaccinated persons (placebo). A Mann-Whitney test was implemented for comparisons. (c) Changes in RBD-binding antibody levels from 4 weeks (day 28) to 6 weeks (day 42) after COVID-19 vaccination. (d) Post-vaccination changes in S-binding antibody levels. Statistical analysis was carried out via a paired, nonparametric Wilcoxon test.