Fig. 4.

Applications of the in-house S1 RBD antibody binding assay. Violin plots showing the reactivity to RBD of serum/plasma samples (diluted 1:80) from convalescent subjects who had tested PCR-positive for SARS-CoV-2 infection (n = 83, blue); COVID-19 hospitalized subjects (n = 146, red); subjects who received full COVID-19 vaccination (n = 283, green); adult residents in the Lakewood, NJ township (high burden) s(n = 148, purple); pre-COVID-19 samples (n = 104; orange); SARS-CoV-2 PCR-negative subjects (n = 103; black). In all panels, the solid horizontal lines represent the median (thick line) and interquartile range (thin lines). Assays were performed in technical duplicates. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)