Fig. 3. Correlation of spike-pseudotyped viral neutralization, RBD-ACE2 blocking and RBD-specific serology results.

Plasma samples from inpatients (n = 188) (A) and outpatients (n = 96) (B) collected at different time points post-onset of symptoms were tested at a dilution of 1:1250 for their pseudovirus neutralization activity. Correlations with RBD IgM, IgG, IgA (1:100 diluted plasma samples), and RBD-ACE2 blocking ELISA (1:10 diluted plasma samples) data were assessed with simple linear regression and 95% confidence bands (grey shading) of the best-fit line. Correlations between RBD IgM, IgG, and IgA data and RBD-ACE2 blocking ELISA results were done on the full sample set from inpatients (n = 714) and outpatients (n = 114). Plots show mean ELISA OD₄₅₀ values of duplicate measurements and average percent neutralization from duplicate testing in each of two replicate experiments.