|Bertran, Kateri - Consultant|
|Lee, Dong-hun - Orise Fellow|
|Pritchard, Nikki - Boehringer Ingelheim Pharmaceuticals|
|Linz, Perry - Boehringer Ingelheim Pharmaceuticals|
|Mebastsion, Teshome - Boehringer Ingelheim Pharmaceuticals|
Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2017
Publication Date: 1/2/2018
Citation: Balzli, C.L., Bertran, K., Lee, D., Killmaster, L.F., Pritchard, N., Linz, P., Mebastsion, T., Swayne, D.E. 2018. The efficacy of recombinant turkey herpesvirus vaccines targeting the H5 of highly pathogenic avian influenza virus from the 2014/2015 North American outbreak. Vaccine. 36:84-90. https://doi.org/10.1016/j.vaccine.2017.11.026.
DOI: https://doi.org/10.1016/j.vaccine.2017.11.026 Interpretive Summary: The highly pathogenic avian influenza virus outbreak in North America during 2014 and 2015 was extremely devastating to the US poultry industry and federal government. The licensed poultry vaccines currently available for use in the U.S. during outbreaks were developed years ago and target older and different influenza virus lineages than the one responsible for the recent outbreak. By developing effective vaccines that target currently circulating strains of avian influenza virus, the USDA can be better prepared with a more effective vaccine if poultry vaccination is required for disease control and eradication in future outbreaks. These studies integrate the recent avian influenza virus lineage target with an established vaccine technology to create three test vaccines. The three vaccines were tested in chickens for their effectiveness against the recent highly pathogenic avian influenza virus. Two of the test vaccines had mixed results while one test vaccine was 100% effective for survival and significantly reduced viral shedding from infected chickens. Further studies of the most effective test vaccine are needed to determine its effectiveness against other lineages and strains of avian influenza.
Technical Abstract: The outbreak of highly pathogenic avian influenza virus in North American poultry during 2014 and 2015 demonstrated the devastating effects of the disease and highlighted the need for effective emergency vaccine prevention and control strategies targeted at currently circulating strains. This study evaluated the efficacy of experimental recombinant turkey herpesvirus vector vaccines with three different inserts targeting the hemagglutinin gene of an isolate from the recent North American influenza outbreak. White leghorn chickens were vaccinated at one day of age and challenged with A/Turkey/Minnesota/12582/2015 H5N2 at 4 weeks of age. Birds were analyzed for survival, viral shedding at two and four days after infection, and specific antibody prior to challenge and from surviving birds. The three experimental vaccines demonstrated 100%, 45% and 15% survival with the most effective vaccine significantly reducing oral and cloacal viral shedding compared to all other groups and generated specific antibody prior to challenge with highly pathogenic avian influenza virus. More studies are needed using diverse H5Nx highly pathogenic virus isolates to fully determine the breadth of coverage against possible exposure strains, as well as possible impact of maternally derived antibody on protection and vaccine efficacy.