The value of vaccination against HPAI as a modality to be incorporated in control programs is receiving increasing consideration. The International Alliance for Biological Standards (IABS) will host a workshop on barriers to usage of vaccination for prevention and control of HPAI in Paris, France, October 25-26. The fact that Dr. David Swayne of the USDA-APHIS will serve as the Head of the Scientific Advisory Committee is more a recognition of his preeminence in the field but does not necessarily represent an endorsement of the principle of vaccination as a preventive or control measure by the USDA-APHIS.
The advance publicity for the meeting is reproduced verbatim for the benefit of Subscribers given the severity of the current H5N1 panornitic. It is hoped that the data presented and the recommendations developed from the Conference will be reviewed by Veterinary regulators and decision makers in the world’s poultry industries
High pathogenicity avian influenza outbreaks around the world are currently causing extensive problems in poultry production and wild birds. Recent outbreaks are among the largest ever experienced in Europe and in North America. More than 157 million birds have died or been destroyed because of these outbreaks, an unacceptably high loss, leading producers, and veterinary authorities in affected countries to explore alternative methods of prevention, in particular, vaccination. In addition, the latest strain has caused extensive problems in poultry and wild birds across the northern hemisphere including Central Asia, Middle East and West Africa.
“The interest in vaccination against high pathogenicity avian influenza is currently very high. As a result, we have now reached capacity for in-person attendance at the meeting and have decided to provide online access to those who aren’t able to attend in person,” said Dr. Rick Hill, president of IABS. The current global outbreak has caused normal management practices allowing free ranging of birds to be suspended and has also caused a severe disruption of supply chains because of the disease and the associated control measures. These outbreaks have occurred because migratory aquatic birds have become vectors for transmission of HPAI virus. Better ways are needed to prevent the virus from spilling over to poultry and spreading from farm to farm once outbreaks occur. Vaccination is one method available, but there are challenges involved.
The IABS workshop will explore these challenges and ways to address them”. Until now, vaccination has been used only sparingly to prevent HPAI in Europe and has not been applied at all in North America. Prevention of HPAI has depended on biosecurity measures, but even some farms that enhanced their biosecurity have still been affected. In other words, alternative measures to boost protection in poultry provided by biosecurity are needed. Well-managed vaccination can do this by increasing resistance to infection, preventing clinical disease and can even stop transmission in an infected flock.
“One of the biggest issues is that there are many barriers to usage of vaccine. Many of these are unnecessary and most can be overcome,” said Dr. David Swayne, Avian influenza specialist and head of the Scientific Advisory Committee for the meeting. “For example, a recent article described avian influenza vaccination as “taboo” but that is only because of misconceptions about vaccination. Preventive vaccination does not change avian influenza status of a country under the World Organisation for Animal Health rules provided an appropriate surveillance program is in place to detect infection. One element that has been missing is agreement on what constitutes an appropriate surveillance program that is also cost-effective for producers. This is one of the areas that will be discussed in detail in the meeting including consideration of novel methods for surveillance.”
Other meeting topics include an examination and discussion of all the barriers to vaccination, ways to overcome them, and how to help design appropriate vaccination programs. There will also be two panel sessions in which options for vaccination programs for preventive and emergency vaccination will be presented. These options will then be discussed by all in-person participants in working groups in order to gather a range of views on ways to deploy vaccines effectively. Remote attendees will be able to provide comments online. “We are already seeing moves in the European Union for uptake of vaccination and this meeting will provide more information on ways that this might be applied,” Dr. Hill said. “This meeting represents an ideal and timely opportunity for anyone with an interest in vaccination against high pathogenicity avian influenza to understand and have an influence on future vaccination strategies against this devastating disease.”
According to Dr. Les Sims, a member of the scientific committee, vaccination has been used successfully in Hong Kong SAR as a preventive measure against HPAI. “In the early 2000s it was evident that biosecurity measures alone could not prevent all incursions of high pathogenicity virus into markets and farms in Hong Kong SAR. As a result, vaccination was added as an additional preventive measure,” Dr. Sims said. “Because of the zero tolerance for infection, vaccination was accompanied by a surveillance program designed to detect infection in vaccinated flocks. Hong Kong SAR now has 20 years of experience to draw on that will be of value for other countries and regions considering how best to use vaccination against this disease.” Dr. Sims also pointed out that there are also other countries where viruses are endemic and vaccination has been used successfully to reduce zoonotic spill over of virus, specifically concerning H5N1 in Vietnam and H7N9 viruses in China. “The difference between places where virus remains endemic in poultry and the preventive vaccination in Hong Kong SAR, and any potential future programs in Europe and North America is that these latter places will retain a zero-tolerance approach to transmission in poultry,” he said. In summing up the expected benefits of this upcoming meeting Dr. Swayne said. “There is little doubt that we will see greater usage of vaccination against HPAI in the future. This meeting will provide a road map on how best to overcome the barriers currently in place. None of us want a repeat of events of the past few years and that is the driver for this very important meeting.