Cross-reactive antibody response to the pandemic A (H1N1) 2009 influenza virus induced by vaccination with a seasonal trivalent influenza vaccine: a longitudinal study of three influenza seasons in Japan

摘要

The cross-reactivity of antibody to the swine-origin pandemic in?uenza A (H1N1) 2009 virus induced by vaccination with a seasonal trivalent in?uenza vaccine was studied. Paired sera from a cohort of adult volunteers vaccinated with a trivalent seasonal in?uenza vaccine every year from 2006 to 2008 were collected each year and tested by hemagglutination inhibition (HI) for antibody against the pandemic in?uenza A (H1N1) 2009 virus. There was little increase in the geometric mean titer overall; a slight increase was detected in the sera obtained in the 2007–2008 season but not in the other two seasons. The proportion of individuals with HI antibody titers ≥ 1:40 did not change signi?cantly from year to year. These results indicate that cross-reactivity of the antibodies induced by a trivalent seasonal vaccine to the pandemic influenza A (H1N1) 2009 virus is marginal.