Fig. 1.

Humoral responses against different strains of SARS-CoV-2 according to vaccination timing and doses after mild COVID-19. a IgG-binding activities measured using an enzyme-linked immunosorbent assay. b Neutralizing activities measured using a live virus neutralization test. c Neutralizing activities based on a pseudovirus neutralization test. Horizontal lines in a denote binding activity values from the negative control specimen. *P < 0.05, **P < 0.005 NS, not significant; FRNT, focus reduction neutralization test; AUC, area under the curve