Fig. 5: Neutralizing activity of plasma samples positively correlated with RBD-IgG titers.

Neutralizing antibody titers are transformed by Log4 and RBD-IgG titers are transformed by Log2. The association between neutralizing antibody titers and RBD-IgG titers is assessed by simple linear regression analysis and two-tailed Spearman’s correlation. Spearman r = 0.6657 (95%CI, 0.5658 to 0.7463). It represents the 95% confidence bands with the best-fit line. PRNT, plaque reduction neutralization test.