FIGURE 7.

Severe acute respiratory syndrome coronavirus 2 IgM (A) and IgG (B) titers tested by an enzyme-linked immunosorbent assay according to the days from symptom onset and stratified by disease severity (severe [hatched red plots] vs nonsevere [filled blue plots]). IgM and IgG antibody levels did not differ according to disease severity (P > .05). Antibody levels are presented as the measured S/CO. The dotted line represents the cutoff value (1.1). The boxplots show medians (middle line) and first and third quartiles (boxes), whereas the whiskers indicate minimum and maximum values. S/CO, absorbance values divided by the cutoff [Colour figure can be viewed at wileyonlinelibrary.com]