Evolution of avian influenza viruses in the context of vaccination

Project summary

While outbreaks of high pathogenicity avian influenza viruses (HPAIVs) were rare in Europe and geographically contained for many years, the situation has dramatically changed in the last few years with thousands of H5 HPAIV outbreaks in domestic poultry, unprecedented spread in wild birds and a record number of spill over events to mammals. Intervention strategies, such as stamping out and biosecurity policies, meant to keep infections under control and prevent the transmission of AIVs in poultry, need to be complemented by other measures. Among them, vaccination of domestic poultry against AIVs, which has long been prohibited due to resulting trade restrictions, is now seen as an extremely relevant alternative to massive stamping-out policies. However, vaccinating domestic poultry against AIVs comes with important challenges.

One of the major challenges is the timely identification of the emergence of novel virus variants, against which existing vaccines may offer decreased protection. We have built the EVIVA project to increase knowledge and contribute to decision-making regarding the evolution of AIVs in the context of vaccination. The project is centred on H5Nx and H9N2, the two major subtypes of AIVs for which vaccination programmes are in place because of their dramatic impact on poultry production systems, their continuous spread and zoonotic potential. A set of techniques will be translated from human medicine to veterinary medicine and applied to monitor and interpret virus evolution. The EVIVA project does not aim at developing new innovative AIV vaccines, but aims at taking into account vaccination programmes that have been or will be implemented in Europe and worldwide. Overall, EVIVA will develop and validate a series of methods, which will be used within to generate fundamental knowledge on the consequences of vaccination on antigenic drift of AIVs and on the correlations of immune protection against AIVs in poultry.