Comparison of European Medicines Agency (EMA) immunogenicity variables for the intradermal and adjuvanted influenza vaccines assessed by haemagglutinin inhibition (HI; left-hand column) and single radial haemolysis (SRH; right-hand column) methods. Analyses were carried out with the other immunogenicity analysis set (participants who received a study vaccine and for whom pre-and post-vaccination titres on days 0 and 21 were available for each strain). The horizontal line indicates the EMA threshold for each variable. (a) Ratio of individual post-and pre-vaccination geometric mean titres (GMTR); (b) Post-vaccination seroprotection rate1 (%); (c) Seroconversion/significant increase rate2 (%).
*: statistically significantly difference between the groups (adjuvanted vaccine -intradermal vaccine) was observed for the A/Solomon (HINI) strain using the full analysis set: 5.8% (95% CI: 1.1-10.5).
1Seroprotection: percentage of participants with anti-HA titre ≥ 40 [1/dil] or ≥ 25 mm2 for HI and SRH methods, respectively.
2Seroconversion: anti-HA post-vaccination titre ≥ 40 (1/dil; HI method) or ≥ 25 mm2 (SRH method) for participants with a pre-vaccination anti-HA individual titre < 10 (1/dil; HI method) or ≥ 4 mm2 (SRH method). Significant increase: ≥ fourfold increase (HI method) or ≥ 1.5-fold increase (SRH method) from pre-to post-vaccination anti-HA individual titre for participants with a pre-vaccination anti-HA individual titre ≥ 10 (1/dil - HI method) or > 4 mm2 (SRH method).
Van Damme et al. BMC Infectious Diseases 2010 10:134 doi:10.1186/1471-2334-10-134