Two companies in the U.S. and Canada have developed cattle-use vaccines that could reduce human illnesses from Escherichia coli O157.
But officials with those companies will not be allowed to make label claims related to human health or food safety or use evidence of such benefits toward gaining approval of the biologics, even though beef producers are considering using the vaccines because of the potential food safety improvement.
The Department of Agriculture's Center for Veterinary Biologics has, since 2005, allowed manufacturers to seek USDA approval of products intended to reduce the colonization or shedding of organisms that cause a carrier state but not disease in the animals receiving the products. In February 2009, the USDA conditionally licensed an E coli O157 vaccine made by Epitopix, a Minnesota-based company, for treatment of a carrier state in cattle.
While the USDA regulates such veterinary biologics, officials with the CVB said claims regarding benefits to human health would require approval by the Food and Drug Administration.
Dr. Jim Sandstrom, general manager of Epitopix, said that while regulations prevent his company from claiming its vaccine could help prevent illnesses, use in tests has been connected with good titers and reduction of E coli O157 in cattle manure.
The Ontario-based Bioniche LIfe Sciences Inc. has received approval in Canada for its cattle-use vaccine to reduce shedding of E coli O157, and the company is waiting for issuance of a conditional license in the U.S.
Rick Culbert, president of Bioniche Food Safety, said the U.S. and Canadian regulatory bodies similarly have no jurisdiction to approve an animal-use vaccine for a human benefit. The label claims have to reference their impact on the animals, such as the reduction of E coli O157 shedding claimed on the label of his company's vaccine.
Culbert also said that, if a study were to indicate use of his company's vaccine reduced E coli in beef from treated cattle, that information could not be used toward approval.
Culbert likened the approval process to that of rabies vaccines, which have been approved on the basis of their impact on animals but largely adopted to prevent rabies in humans. However, he noted that E coli O157 infections are different in that they are subclinical in cattle and that cattle do not benefit from vaccination against the bacteria.
Dan Schaefer, assistant vice president of research and development for Cargill Beef, expressed hope about the potential use of E coli O157 vaccines to improve food safety and increase consumer confidence. His company collaborated with officials from Epitopix, Kansas State University, Texas Tech University, and the Beef Checkoff Program on a commercial study in summer 2010 involving 85,000 cattle in feedlots, 58,000 of which received two doses of vaccine. More testing is planned for summer 2011.
Dr. Daniel U. Thomson, the Jones Professor of Production Medicine at Kansas State University, has studied the Epitopix vaccine and worked on challenge and field studies, and he says cattle-use E coli O157 vaccines could increase veterinarians' on-farm role in food safety. Current research at his university includes investigation into whether use of the vaccine could provide cross-protection against strains such as those that cause neonatal calf diarrhea, also known as scours.