Hemagglutination inhibition antibody and virus neutralization titres in post-LAIV ferret serum samples in study FER-16–09. Serum samples were collected 21 days after HK LAIVs, SW LAIVs and TX LAIVs vaccination and HI titers (A, C, E respectively) or neutralizing (B, D, F respectively) titers were estimated. All Pre-LAIVs serum samples (−14 DPI) were HI-negative. HI titre in Mock samples were below the limit of detection (1/5). Serum samples from ferrets F3856 (SW LAIV 6:2) and F3859 (TX LAIV 5:3) were negative and excluded from analysis. LAIVs 5:3 and LAIVs 6:2 vaccinated groups data are visualized in blue and red colors respectively. Test antigens are shown on the x-axis. Dotted line denotes assay limit of detection. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)