Abstract Title
Efficacy of Inactivated RG H5N2 Vaccination Strategies in Pekin Ducks: Implications for HPAI Control and Transmission Mitigation
Abstract
Recent outbreaks of highly pathogenic avian influenza (HPAI) clade 2.3.4.4b H5N1 have significantly impacted poultry production in North America, necessitating urgent control measures. This study investigates the efficacy of an inactivated reverse genetics H5N2 (H5N2rg) vaccine with the HA protein derived from the A/turkey/Indiana/22-003707-003/2022, H5N1 (Zoetis Inc). Single dose and prime-boost (two-dose) vaccination strategies were compared in Pekin ducks. Our findings indicated that while single dose vaccination reduced mortality, it resulted in less uniform antibody responses and allowed for some virus shedding and transmission to contact birds. Conversely, prime-boost vaccination provided sterilizing immunity, as evidenced by 100% survival and no detectable virus shedding in vaccinated ducks post-challenge with HPAI H5N1. Contact transmission studies indicated that vaccinated ducks did not shed virus when housed with other vaccinated birds, whereas significant shedding occurred among unvaccinated ducks exposed to challenged birds, leading to mortality in naïve contact ducks, turkeys, and chickens. These results highlight the importance of vaccination strategies in mitigating HPAI outbreaks. The potential for differentiation between vaccinated and infected flocks can facilitate international trade, underscoring the need for robust vaccination protocols alongside biosecurity measures. This study supports the integration of vaccination as a crucial component in managing HPAI risks in poultry, particularly in light of evolving viral strains and their economic implications for the industry.
Co-Author(s)
Frizzo da Silva, Leticia (Zoetis Inc), Tamiru N Alkie (CFIA), Sugandha Raj (CFIA), Gregory P Nitzel (Zoetis Inc.), Henok Gebrebrhan (CFIA), Wanhong Xu (CFIA), and Yohannes Berhane (CFIA)
Abstract Category
Diagnostics, vaccination, or other mitigation strategies for poultry and wildlife