Abstract Title
OFFLU Avian Influenza Vaccine Matching (AIM) project
Abstract
Background: OFFLU has developed a system for providing information from multiple sources to countries on the antigenic characteristics of circulating high pathogenicity avian influenza (HPAI) A(H5Nx) viruses of the Goose/Guangdong/1/96-lineage to support vaccine antigen updates, given the recent increase in countries vaccinating poultry against H5 viruses. Methods: Reference antisera were produced in chickens using virus isolates representative of circulating clades or available poultry vaccine seed strains. Hemagglutination inhibition (HI) assays were performed and antigenic cartography used. Multiple clade viruses between 2020–2025 were analysed. Information is presented with peer-reviewed data. Results: Vaccine antigens not within clade 2.3.4.4 are antigenically distant from clade 2.3.4.4b viruses and are not expected to be suitable candidate antigens for inactivated whole virus vaccines against these strains. Subtype-specific heterogeneity over previous years was noted in antigenic distances for clade 2.3.4.4b viruses. In geographically restricted regions, there is evidence of antigenic drift in viruses isolated from poultry. Clade 2.3.2.1 and clade 2.3.4.4 viruses are antigenically distinct from older virus clades including antisera raised against clade 1, 2.2, or 2.3.4 viruses. Vaccine trials have demonstrated that various commercially available vaccines provide clinical protection against recent H5N1 clade 2.3.4.4b viruses. Experimental studies may not reflect the field situation and trials with chickens may not be applicable to other species. Continued monitoring for genetic and antigenic changes, especially in countries where the virus is enzootic in poultry is crucial for early detection of antigenic change and response to update vaccines where necessary.
Co-Author(s)
Amelia Coggon1,2, Ashley Banyard3, Francesco Bonfante4, Joshua Linton-Jenkins3, Joe James3, Silvia Maniero4, Frank Wong5, Joanne Grimsey5, Erica Spackman6, Jiho Lee6, Gounalan Pavade7, David Swayne1, Nicola Lewis2, Leslie Sims8, Ian Brown9
1.Food and Agricultural Organization of the United Nations
2.Royal Veterinary College
3.Animal Plant and Health Agency
4.Istituto Zooprofilattico Sperimentale delle Venezie
5.CSIRO Australian Centre for Disease Preparedness
6.US National Poultry Research Center, USDA-ARS
7.The World Organisation for Animal Health
8.Asia Pacific Veterinary Information Services
9.The Pirbright Institute
Abstract Category
Diagnostics, vaccination, or other mitigation strategies for poultry and wildlife