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Dairy, Turkey and Egg Industries Request Preventive H5N1 Vaccination

08/20/2024

In an August 16th letter addressed to the USDA Secretary of Agriculture, United Egg Producers, the National Turkey Federation and the National Milk Producers Federation requested USDA to adopt “a sense of urgency and preparedness” to support vaccination of dairy cows, turkeys and egg laying hens.  In the joint request, the industry associations outlined the economic losses associated with H5N1 influenza experienced by producers, the public sector and ultimately by consumers.  The letter did not, however, add sufficient stress on the probability, even extremely remote, of the emergence of a zoonotic and possibly even contagious strain of H5N1 that could result in a devastating pandemic. The letter to the USDA Secretary made reference to the obstacles to adoption of vaccination represented by an inevitable but non-quantified impact on exports of broiler leg quarters and feet.

 

USDA has been less than enthusiastic in promoting adoption of vaccination among importers of U.S poultry products. Vaccination with appropriate surveillance is accepted by the World Organization of Animal Health as an adjunct to biosecurity.  The reluctance to embrace vaccination by the USDA is possibly due to the misplaced and by now discredited policy of attempting to eradicate HPAI in poultry flocks by stamping out each successive outbreak.  Despite depopulation of close to 90 million commercial birds, predominantly egg production flocks, over the past two years, the temporal occurrence has extended beyond the spring and fall migratory seasons for waterfowl and in addition a spatial and species expansion has occurred with confirmation of infection among free-living mammals, resident birds and dairy cows.

 

 It is axiomatic that it is impractical to attempt to eradicate an endemic disease over the short term when confronted with a large reservoir of infection and with constant reintroduction of the causal virus.  Vaccination should be adopted for egg production, and turkey flocks in high-risk areas under flyways transited by migratory waterfowl and in the vicinity of their nesting habitat. 

 

The requirements imposed by the WOAH regarding vaccination incorporate surveillance for infection among immunized flocks. With current technology including PCR, it will be possible to certify that flocks to be processed for export are free of infection within 24 hours of harvest and that product is also free of HPAI virus.  Reliance on serology and the oft-repeated canard that it is difficult to distinguish between vaccinated and infected flocks should be discounted as a restraint to preventive vaccination.

 

Perhaps the missionary work undertaken by USDA-APHIS within the World Organization for Animal Health has lacked intensity or has been misdirected.  In the first instance, turkey and egg producers and their new-found supporters in the dairy industry should concentrate their efforts on the NCC, representing broiler producers.  Simply stating that introduction of vaccination would seriously impair exports is a simplistic overreaction.  Close to 45 percent of nations receiving either leg quarters or feet either have endemic or seasonal outbreaks of avian influenza or have used or are using vaccination as a control measure. In the case of Canada and some other nations, bilateral agreements determine the extent and mechanisms for export usually with zoning as the determining factor.

 

Since federal agencies are congenitally opposed to change, especially when this requires admitting to failure of previous policies, we can expect the adoption of vaccination to be deliberately delayed by the USDA. As an institution the USDA will fall back on the expedient of conducting risk assessments or the need to develop  “new” vaccines or alternatively conducting time-consuming laboratory and field trials confirming that commercially available products as widely used internationally are effective. 

 

The need for action as requested in the August 16th letter is regrettably about two years late.  It is only the emergence of bovine influenza H5N1 caused by the B3.13 mammalian-adapted variant that has stimulated a reappraisal of vaccination by the two most affected poultry industry segments.  There is no need to reinvent the wheel with new USDA-ARS vaccines or to “evaluate” the effectiveness of currently available commercial products from reputable multinational manufacturers. We have data from many nations including Mexico and France

 

This commentator, committed to the long-term wellbeing of the poultry industry has developed a perspective based on both professional training and then commercial experience since 1968, encompassing live-bird management, academia and the allied industry. Exposure to production on four continents has facilitated perceptions and understanding, integrating veterinary epidemiology with economics and practical considerations. Above all, application of the One Health principle raises caution over a possible mutation whereby H5N1 may become a human health issue, a concern expressed by the World Health Organization and numerous virologists in the U.S., Asia and Europe.

 

Let us therefore reject a parochial approach promoted by a single segment of the industry in applying pressure to deny vaccination for the egg-production and turkey operations in high-risk areas. A program can be developed to optimize benefits to producers, exporters of U.S. poultry products, veterinary regulators and consumers. Above all by creating an immune poultry population through vaccination, the risk of an emergent zoonotic strain of HPAI with epidemic potential will be markedly reduced. 

 

The August 16th request for the USDA to consider vaccination is an important step, since this places the APHIS on notice that attempts at eradication are futile. Vaccination offers an alternative and contributory modality to biosecurity to prevent infection in poultry flocks and now in the dairy segment of the livestock industry.  Newcastle disease, in every way was as destructive as avian influenza during the 1960s and 1970s. This disease was successfully suppressed but not eradicated, by vaccination.  Avian influenza is effectively “the Newcastle disease of the 2020s” and should be addressed by creating immune poultry populations through application of currently available effective vaccines.