Fig. 3: Reduced SARS-CoV-2 neutralizing activity in children with and without MIS-C compared to adults with mild and severe COVID-19.
a, Plasma neutralizing activity in the pseudovirus assay was correlated with the end point titers in a live virus microneutralization assay based on the inhibition of the cytopathic effect (n = 13; Methods). b, The neutralizing activity for SARS-CoV-2-specific antibodies was determined using the pseudovirus assay (Methods). Neutralizing activity is shown from adult CPDs (open black squares, n = 19), adult patients with COVID-19-induced ARDS (COVID-ARDS, closed red squares, n = 13), pediatric patients with a history of SARS-CoV-2 infection but not MIS-C (non-MIS-C, open blue circles, n = 31), patients with MIS-C (closed green circles, n = 16) and control plasma from pre-pandemic donors (negative control, gray triangles, n = 10). The black bar indicates the median + IQR. The P values were calculated by one-way ANOVA with Šidák’s multiple comparisons test (CPD versus COVID-ARDS: P = 0.019; CPD versus pediatric non-MIS-C: P = 0.0031; COVID-ARDS versus MIS-C: P = 3.35 × 10−6; pediatric non-MIS-C versus MIS-C: P = 1.0). Significance is indicated as *P < 0.05, **P < 0.01, ***P < 0.001 or P > 0.05 (NS). c, The percentage inhibition values of S protein–mediated pseudoviral replication plotted against the plasma dilution factors for all individuals in each group are shown. d,e, Neutralizing activity was plotted against anti-S IgG levels (d) and patient age (e) in the adult (left) and pediatric (right) cohorts. The best fit lines and P values (reported to four decimal places) were calculated using simple linear regression. Neutralizing activity versus anti-S IgG (CPD: R2 = 0.29, slope = 0.36, y-intercept = 0.88; MIS-C: R2 = 0.51, slope = 0.38, y-intercept = 0.43; pediatric non-MIS-C: R2 = 0.21, slope = 0.22, y-intercept = 0.86). Neutralizing activity versus age (pediatric non-MIS-C: R2 = 0.20, slope = −0.034, y-intercept = 1.64).
