Immune Responses Induced by Different Licensed Influenza Vaccines

There are currently five licensed inactivated influenza vaccines approved for use in the United States by the Food and Drug Administration.Current influenza virus vaccines consist of 3 components: the HA protein from an H1N1 virus, an H3N2 and an influenza B virus.Influenza vaccines are evaluated and approved by the FDA on the basis of HA and NA content. However, different manufacturing processes are involved in the preparation of these commercial vaccines and evidence suggests that each of these vaccines contain similar patterns of HA protein but different patterns of influenza influenza internal proteins such as NP and M1. The presence of these additional internal proteins of influenza virus which are targets of T cell responses suggest not only the potential for additional protection derived from influenza vaccines other than antibody mediated protection but also differential levels of T cell mediated protection between different manufacturers of commercial influenza vaccines.Each subject will have four blood samples taken- prevaccination and at Days 7, 14,30 and 3-5 months post vaccination. These samples will be tested for T and B cell responses and the results compared between different manufacturers.