Submitted to: World Veterinary Poultry Association
Publication Type: Proceedings
Publication Acceptance Date: April 16, 2011
Publication Date: August 15, 2011
Citation: Spackman, E., Mckinley, E.T. 2011. Protection of chickens to antigenically variant avian influenza virus challenge after immunization with two antigenically unrelated strains of the same subtype. In: Proceedings of the 17th Congress of the World Veterinary Poultry Association, August 14-18, 2011, Cancun, Mexico. p. 244-245. Technical Abstract: The antigenic diversity of avian influenza virus (AIV) within a subtype has been well established and is believed to be driven by the selection of immunologic escape mutants. In regions where vaccination against AIV has been implemented for prolonged periods (e.g. Vietnam and Egypt), vaccines which were initially efficacious have reduced protection against recent strains. Therefore, to achieve optimal protection it is necessary to periodically update the vaccine strains. One possible approach which may extend the antigenic life and which may confer broader immunity is to vaccinate either simultaneously or successively with AIV strains of the same subtype, but which are antigenically different. We have evaluated this approach in chickens with several highly pathogenic H7 subtype AIVs. Initial data suggests that the number of vaccinations may be more important than the antigenic composition of the vaccines. Additional studies are underway to confirm these results.