Fig. 1: Stratification of vaccinees.

Serum samples derived from vaccinees at baseline and 21 or 70 days after vaccination in the seasons 2014/15 and 2015/16 were used for quantification of influenza antigen-specific antibodies (HAI assay). Venn diagrams depict overlapping responses against the three vaccine antigens (1st study n = 34, 2nd study n = 200 biologically independent samples). Adapted from ref. 46, copyright by the co-author F.P. Source data are provided as a Source Data file.