Figure 2.

Proportion of the 90 substudy patients who seroconverted

Seroconversion was defined as a change from negative (anti–hemagglutination immunoglobulin G titer <10) to seroprotected after vaccination or a fourfold increase in titer if 10 or higher at baseline according to US Food and Drug Administration (FDA) and European Medicines Agency (EMA) seroconversion benchmark guidelines (≥40%).12,13 A/H1N1, A/California/7/2009; A/H3N2, A/Texas/50/2012; B, B/Massachusetts/2/2012; CI, confidence interval.