Title: Current developments in avian influenza vaccines including food safety aspects in vaccinated birds Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 2007
Publication Date: March 20, 2007
Citation: Swayne, D.E., Suarez, D.L. 2007. Current developments in avian influenza vaccines including food safety aspects in vaccinated birds [abstract]. In: Abstracts of OIE/FAO/IZSVe Scientific Conference on Vaccination: A tool for the Control of Avian Influenza, March 20-22, 2007, Verona, Italy. p. 39. Technical Abstract: Historically, vaccines against avian influenza (AI) have had more limited use in poultry than vaccines for other poultry diseases such as Newcastle disease (ND) and infectious bronchitis. These AI vaccines have been primarily based on low or high pathogenicity (HP) AI viruses that were grown in embryonating chicken eggs, chemically inactivated, emulsified in mineral oil adjuvant, and injected into individual birds. Recently, fowlpox and avian paramyxovirus type 1 vectored vaccines with AI H5 gene inserts (+ or - N1 gene insert) have been developed and licensed, but they also required individual bird injection. Emerging technologies may overcome existing limitations and result in vaccines that can be grown in tissue culture systems for more rapid vaccine production; provide optimized protection as the result of closer genetic relationship to field viruses; can be mass applied by aerosol, drinking water or in ovo administration; and provide easier strategies for identifying infected birds within vaccinated populations, i.e. DIVA. These technologies include AI viruses with partial gene deletions, AI-ND virus chimeras and vectored vaccines using adenoviruses, Marek’s disease virus and sub-unit vaccines. These new technologies should be licensed only after demonstration of purity, safety, efficacy and potency against AI viruses, and for live vectored vaccines restriction of viral transmission to unvaccinated birds. Usage of vaccines in HPAI infected countries not only will provide protection to poultry, but will provide additional safety to the consumer. Experimental studies have shown that AI immunized birds following HPAI virus challenge lack virus in meat and eggs, and greatly reduced replication and shedding from respiratory and alimentary tracts.