Cytokines in nasal swabs. A Concentrations of IL-1β, IL-6 and IL-8 for each infected group. Each line within the graphs represents an individual within the indicated group. B Principal component (PC) analysis for IL-6, IL-8 and IL-1β. Scatterplot with vectors showing the direction and strength of the correlation of IL-6, IL-8, IL-1β, virus titre and time along PC1 and PC2.