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. Author manuscript; available in PMC: 2017 Dec 15.
Published in final edited form as: J Infect Dis. 2016 Aug 28;214(10):1477–1486. doi: 10.1093/infdis/jiw380

Figure 4.

Figure 4

The effect of prior seasonal vaccination on hemagglutination-inhibition (HI) responses. Induction of HI titers by 2010–2011 trivalent inactivated influenza virus (TIV) was assessed in subjects who received prior influenza vaccination during the 2009–2010 influenza season (V) and those who did not (UV). Vaccination with prior seasonal influenza vaccine and monovalent 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) vaccine were assessed separately. HI titers to influenza virus strains included in the 2010–2011 TIV (A[H1N1]pdm09, A/Perth/16, and B/Bris/60), the 2009–2010 TIV (A/Bris/59, A/Bris10, and B/Bris/60), and the 2008–2009 TIV (B/Flor/4) were assessed at 0 days, 28 days, and 1 year after vaccination. Differences between previously vaccinated and unvaccinated subjects were determined using unpaired t tests. Error bars represent 1 standard error. Significance is indicated by *P ≤ .05 and ***P ≤ .001.