Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/5/2015
Publication Date: 7/10/2015
Citation: Kapczynski, D.R., Pantin Jackwood, M.J., Spackman, E., Suarez, D.L., Swayne, D.E. 2015. Protective efficacy of recombinant and inactivated H5 avian influenza vaccines against challenge from the 2014 intercontinental H5 highly pathogenic avian influenza viruses (H5N8 and H5N2) [abstract]. American Association of Avian Pathologists. CDROM.
Technical Abstract: Protective immunity against highly pathogenic avian influenza (HPAI) largely depends on the development of an antibody response against a specific subtype of challenge virus. Historically, the use of antigenically closely matched isolates has proven efficacious when used as inactivated vaccines. More recently, the use of recombinant live AI vaccines expressing a hemagglutinin (HA) gene from an individual isolate have proven effective against multiple lineages of HPAI. Because of the recent isolation of H5N8 and H5N2 HPAI in wild birds and commercial poultry in the Northwest U.S., vaccine protection in poultry was tested against a wide spectrum of vaccine viruses. In this study, we compared protection of chickens provided by numerous inactivated and recombinant vaccines against the intercontinental H5N8 and the North American reassortant H5N2 HPAI isolates. Groups of chickens (n=10 each) received a single inactivated vaccine which included: U.S.D.A. H5 master seed isolates (H5N9 and H5N2), Chinese reverse-engineered vaccines (Re-5 and -6), homologous HPAI vaccines (H5N8 and H5N2), and a sham vaccinated group. Birds were vaccinated at three weeks of age and challenged at 6 weeks of age with 106 50% egg infectious doses (EID50) per bird of either H5N8 or H5N2 HPAI. In addition, two groups of birds received vaccines with commercial recombinant products and were challenged at 4 weeks of age as above. Protection from challenge, morbidity, virus shedding, and antibody responses from each group will be discussed.