Figure 6.

Impact of demographic features of Cuban COVID-19 recovered patients on the magnitude and quality of the anti-RBD antibody response. Anti-RBD IgG titer was determined by RBD ELISA. Serum samples were incubated on plates coated with the RBD-mFc and were detected with an anti-human IgG antibody conjugated to horseradish peroxidase (HRP). Half-maximal inhibitory dilution (ID50) was determined by surrogate virus neutralization test (sVNT). Inhibition of binding of RBD-mFc to hACE2-hFc was assessed after preincubation of RBD-mFc with sera samples. Spearman correlation was used to determine the association between the age of convalescents and (a) anti-RBD titer and (b) ID50. Stratified sera according to skin color (white, mixed, and black) or their sex (female and male) were tested by (c and e) RBD ELISA and (d and f) sVNT, respectively.