Fig. 2: Pre-existing cross-reactive antibody levels are poorly predictive of protection against infection but correlate with delayed onset of viral shedding.

a Plasma and b mucosal lining fluid IgG, IgM and IgA against hCoVs 229E, HKU1, NL63 and OC34 spike, SARS-CoV-1 spike and SARS-CoV-2 spike and nucleocapsid in the infected (n = 18) and uninfected (n = 16) groups measured at baseline (day −1) by MSD (transiently infected shown as grey triangles, n = 5). c Correlation matrix heatmap showing Spearman correlations between baseline antibody level and time to qPCR positivity in days corrected for multiple comparisons by false discovery rate (FDR). d Two-sided spearman correlation between time to qPCR positivity and duration of qPCR positivity in days. Median lines and IQR are shown. Two-sided multiple Mann–Whitney unpaired tests corrected for multiple antigen and isotype comparisons (Holm-Å Ãdák’s) was used to show significance between the two groups. *p < 0.05.