Fig. 4.
Individual timelines of plasma SARS-CoV-2 nucleocapsid antigen concentration (top panel, green diamond, left side y axis), respiratory swab RT-qPCR Ct values (top, orange + for positive RT-qPCR, orange × for negative RT-qPCR, right side inverted y axis), and anti-N antibody concentrations (bottom panel, red circle for IgA, blue square for IgG, purple triangle for IgM) by days from symptom onset. The dashed horizontal line represents threshold of positivity for both plasma antigen and respiratory RT-qPCR. Inpatient 2 and ICU patient 9 are examples of the majority of antigen-positive individuals whose seroconversion coincided with disappearance of plasma antigen (A and B). Inpatients 4 and 5 and ICU patient 2 all had positive respiratory RT-qPCRs >1 month after earlier viral RNA clearance, without reappearance of plasma antigen (C–E). Plots for all 83 individuals with >1 plasma sample in this study can be found in Supplemental Fig. 6.