Fig. 3: Representation of the pediatric COVID-19 population as a cluster of points for relevant antibody combinations and principal component analysis (PCA).

a, b Cluster representation of S1, S2′, S2 antibodies combination. a The pediatric COVID-19 population versus the negative population, b the pediatric COVID-19 population versus the adult COVID-19 population (for the sake of clarity, the three populations were not represented on the same graph here). c Cluster representation of N, ORF3d, ORF8 antibodies combination, for the pediatric COVID-19 population versus the adult COVID-19 population and the negative population. Samples are represented according to their values of SARS-CoV-2 individual LIPS antibodies as (x, y, z) in the space. For the sake of clarity, only n = 144 pediatric COVID-19 (red), n = 71 adult COVID-19 (blue), and n = 48 negative (gray) samples are represented (a–c). d–f PCA of 14 antibodies analyzed in COVID-19 pediatric patients. Dim1 explains 20.6% of the variation, while Dim2 explains 17.7% of the variation. d Contribution of variables on dimensions 1 and 2. The red dashed line on the graph above indicates the expected average contribution. e Correlation circle and contributions. The scale of contributions is indicated (right). f Summary of contribution of variables on the different dimensions. g, h Factorial plots of PCA on dimensions 1 and 2. The plot is colored by sample types (Adults positives, Pediatrics positives, negative controls) (g), the largest point in shape in each group is the group mean point (circle is for Adult positives, squares for Pediatric positives, triangle for Negative controls) or by symptoms (h).