Fig. 2.

Kinetic changes in neutralizing activity (PRNT₅₀) in recovered MERS patients who had pneumonia. (A) Kinetic changes in neutralizing activity (PRNT₅₀) in serum samples collected from recovered MERS patients who had pneumonia (G-II and G-III) are presented. G-II + G-III: left graph, G-II (green) or G-III (red): right graph. Box and whisker (min to max) plots, including the median value (solid line), are presented for each indicated time point (G-II: n = 10–23 and G-III: n = 9–16). For comparisons of values at the indicated time points, statistical analysis was performed using one-way ANOVA, followed by the Newman–Keuls t-test. ∗, p < 0.05. (B) Correlations of OD ratios against the S1 antigen with neutralizing antibody titres against MERS-CoV (PRNT₅₀) were assessed using linear regression analysis (black line) with 95% confidence intervals (gray) and the Pearson correlation test (coefficient and p value are presented). (C) Kinetic changes in OD ratios against the S1 antigen (blue) and neutralizing activity (PRNT₅₀, red) in serum samples collected from 19 recovered MERS patients without negative seroconversion during the study period. Linear regression analysis (solid line) with 95% confidence intervals (shaded cyan and orange represent OD ratios and neutralizing activity, respectively) was performed to calculate the half-life (OD ratio: 107 months and PRNT₅₀: 20 months).