In an April 22nd position statement, the American Association of Avian Pathologists (AAAP) reviewed current realities relating to vaccination of commercial poultry. At the outset, the Association recognizes that highly pathogenic avian influenza (HPAI) is endemic in the U.S. and has affected all sectors of the poultry industry and has now emerged in dairy herds. Concurrently infection has been diagnosed in terrestrial mammals, companion animals, and 
domestic wild birds in addition to migratory marine species and waterfowl. The AAAP panel responsible for the position statement points to the susceptibility of commercial poultry species and the failure to suppress the epornitic in commercial flocks since emergence of infection in 2022.
A case is made for vaccination consistent with the advocacy by EGG-NEWS over the past three years. Creating immune populations, especially in high-risk areas, will reduce the incidence rate by minimizing the susceptibility of flocks that will continue to be exposed to infection.
The position statement recognizes technical limitations relating to vaccination, the most important of which is failure to elicit sterile immunity. Vaccinated flocks if infected will shed virus although at a lower rate and extensive mortality will be suppressed.
The major restraint to deployment of commercially available vaccines of various types relates to the potential for trade embargos despite the acceptance of vaccination as an adjunct to biosecurity by the World Organization of Animal Health (WOAH). Vaccination against avian influenza using rHVT-H5 vaccines has proven effective in the Netherlands, Italy and Belgium. Other studies have shown the protective effect of inactivated oil emulsion H5 vaccines in numerous countries as a primary immunogenic agent or as a booster.
It is possible to establish a program of surveillance over vaccinated flocks including quantifying immune response applying serology and to confirm freedom from HPAI using PCR. Available technology and logistics can be applied to certify that export consignments derived from specified flocks are free of infection at the time of harvest.
Currently, trade in poultry products and especially broiler meat is subject to a patchwork of regulations imposed by importers. The most extreme restrictions demand nationwide bans or less onerous state or provincial embargos. The reactions of importers are based on outmoded traditional approaches to control of catastrophic infections, to protect domestic industries from competition or as an economic weapon. The World Organization of Animal Health accepts vaccination as an adjunct to biosecurity if conducted in accordance with established surveillance.
With the advent of HPAI in Brazil, the infection can be regarded as a panornitic and accordingly, trade should be regulated in accordance with sound epidemiologic and scientific principles. It is now incumbent on exporting nations to press for adoption of uniform policies on diagnosis of avian influenza, control measures including vaccination, enforcement of regionalization and compartmentalization and harmonizing documentation.
USDA-APHIS has long labored under the misconception that HPAI can be eradicated by a program of sequential depopulation. The Agency has not responded to the endemic status of the infection, involving seasonal reintroduction and dissemination of HPAI virus by migratory waterfowl, the potential reservoir status associated with terrestrial mammals and free-living domestic birds and the reality of aerogenous transmission. An inflexible adherence to past policy has impeded rational decisions relating to suppression of the infection.
The justifiable concern by the broiler segment of the U.S. poultry industry relating to export embargos should not continue to restrict the deployment of avian influenza vaccination in high-risk areas for egg-production and turkey grow-out flocks. The cost to the public sector for indemnity and logistics in addition to the burden borne by consumers far outweighs the potential benefits accruing to broiler exports. The emergence of bovine influenza-H5N1 raises the issue albeit remote of the possibility of mutation to become a zoonotic pathogen capable of contagion. This eventuality should influence veterinary and public health agencies to implement protection of flocks by regulated and strategic vaccination, as advocated by the AAAP.