Figure 1.
Hemagglutination inhibition (HAI) titers against 2009–2010 seasonal vaccine strains.
Serum samples collected from US healthy volunteers vaccinated with 2009–2010 inactivated unadjuvanted trivalent influenza vaccine (TIV) were tested by HAI assay using 0.5% turkey erythrocytes. The geometric mean titers (GMTs), the seroprotection rates (the proportion of subjects having an HAI titer ≥40) before and 21 days after TIV administration, and the seroconversion rates (the proportion of subjects having a ≥4-fold increase in HAI titers) were plotted according to the age distribution of vaccinees for A/Brisbane/59/2007 (H1N1) (A and D), A/Uruguay/716/2007 (H3N2) (B and E), and B/Brisbane/60/2008 (C and F), respectively. The 95% CI for individual HAI GMTs are shown as error bars. The dotted lines indicate HAI titer of 40.
Figure 2.
Hemagglutination inhibition (HAI) titers against 2009 pandemic H1N1 viruses.
Serum samples collected from US healthy volunteers vaccinated with 2009–2010 inactivated unadjuvanted trivalent influenza vaccine (TIV) were tested for cross-reactivity against 2009 pandemic H1N1 viruses by HAI assay using 0.5% turkey erythrocytes. The pandemic influenza specific seroprotection rates (the proportion of subjects having an HAI titer ≥40) before and 21 days after TIV administration and the seroconversion rates (the proportion of subjects having a ≥4-fold rise in HAI titers) were plotted according to the age distribution of vaccinees for A/California/07/2009 (H1N1) (A and F), A/Iraq/8529/2009 (H1N1) (B and G), A/Ontario/RV3226/2009 (H1N1) (C and H), A/South Carolina/18/2009 (H1N1) (D and I) and A/England/195/2009 (H1N1) (E and J), respectively. * indicates the corresponding seroconversion rate in panel F, G, H, I, and J.
Figure 3.
Correlation of antibody titers specific for seasonal vaccine strains and pandemic viruses after seasonal vaccination.
Serum samples were collected on 21 days after administration of 2009–2010 inactivated unadjuvanted trivalent influenza vaccine (TIV) in US healthy adults and elderly. An HAI assay was performed using 0.5% turkey erythrocytes. A correlation analysis between seasonal strain specific HAI titers and pandemic strain specific HAI titers was performed using nonparametric Spearman's ρ test by JMP Version 7. The scatterplots of HAI titers are shown in the presence of 95% bivariate normal density ellipses (indicating the distribution of 95% of individual data points plotted) and corresponding p values. A, A/California/07/2009 (H1N1) vs A/Uruguay/716/2007 (H3N2); B, A/South Carolina/18/2009 (H1N1) vs A/Uruguay/716/2007 (H3N2).
Table 1.
Demographic characteristics of the subjects vaccinated with 2009–2010 seasonal inactivated trivalent vaccine.