no other poultry vaccine available via water , page-2

Many hundreds of millions of doses of the existing avian influenza vaccines have been administered since the commencement of this outbreak. In the last twelve months alone Indonesia sought to vaccinate 300 million chickens and Vietnam has announced plans to vaccinate 415 million birds this year.

Vaccines currently registered for control of Bird Flu all have significant limitations.

Live attenuated flu virus vaccines and killed flu virus vaccines – safety risk - The administration of these traditional vaccines poses a high risk of mutating and forming new and possibly more virulent strains of Bird Flu.
Pox vectored vaccines – economically non viable for broiler market - are available in some south east Asian countries and Mexico. While avoiding the problems of the traditional flu virus vaccines, these must be individually injected into each bird twice at an interval of 14 days. As speed and labour costs are critical these vaccines are not considered viable for mass producing poultry broiler markets.
The Imugene Bird Flu vaccine under development solves the limitations of existing treatments.

Safety
Imugene’s trial vaccine utilises the Adenoviral Delivery Vector platform technology to deliver the necessary genetic material to stimulate the birds' immune responses against the Bird Flu virus. Through the delivery of a very small portion of the flu genetic material to poultry the immune system is stimulated. An immune response is triggered and protection is then provided from the flu virus. The safety advantage is a result of only a very small portion of the genetic composition of the Bird Flu virus being used. This vaccine technique is far safer than live or killed attenuated vaccines as the risk of recombination with the wild type virus or human influenza strains is virtually eliminated.

Compounding the problem with the existing live vaccines is that during an avian influenza outbreak, diagnostic tests cannot distinguish vaccinated (uninfected) birds from those affected by the disease. As Imugene’s vaccine delivers only a portion of the flu genetic material, instead of the whole virus, it is possible to distinguish between vaccinated and infected birds. This translates into the major benefit of allowing countries to undertake a vaccination program to protect whole areas or countries whilst still maintaining surveillance for disease outbreaks and ensuring human safety. As the vaccinated birds can be differentiated from infected birds, export markets are safely protected.

Viability
The trial vaccine enjoys the advantages of the Adenoviral Delivery Vector and therefore is cost effective to administer on a mass scale, via water to poultry.

Current studies
Construction of Imugene’s Bird Flu vaccine candidates has occurred throughout the year. Recent studies and trialling continues to assess the ability of these experimental constructs to elicit circulating antibody responses to the avian influenza strain in chickens.

This approach will allow a more quantifiable assessment of the response of the birds to the vaccine candidate to determine the appropriate dosage, timing and route of administration. Following review and assessment of this data, the most appropriate combinations will progress to final challenge trials.

These challenge trials must be undertaken with extreme care due to the danger of working with the H5N1 Bird Flu virus. Understandably, governments, laboratories and workers wish to minimize exposure or risk to such a deadly virus. Accordingly, Imugene is undertaking as many of the trials it possibly can, using antibody response measurements rather than full challenge trials.