New Foot and Mouth Disease Animal Vaccine on Fast Track

by Rishma Parpia

Published November 2, 2019 | Vaccination, Future Vaccines

Story Highlights

Global pet and animal vaccine manufacturer, Zoetis, has signed an agreement with Texas A & M to develop a new animal vaccine for foot and mouth disease (FMD).
Recently agriculture groups have insisted that USDA develop FMD vaccine bank to prepare for a future FMD outbreak among livestock in the U.S., even though the last outbreak occurred in 1929.
Animal vaccine experts have said there are 23 different strains of FMD viruses and pre-vaccinating animals is not a viable option due to implications for exports.
Since pre-vaccinating is not an option, Iowa State University has developed a new test to differentiate between FMD vaccine strain antibodies and wild type virus antibodies should an outbreak occur in the U.S.

Zoetis, Inc., the world’s largest manufacturer of drugs and vaccines for pets and livestock has signed an agreement with Texas A&M University’s Health Science Center for Innovation and Advanced Development and Manufacturing (CIADM) to develop a new animal vaccine for foot and mouth disease (FMD). The contract will establish a facility at Texas A&M for accelerating the development of vaccines for trans-boundary and emerging diseases, and creating a new vaccine to prevent foot and mouth disease (FMD) in livestock will be the initial focus.¹
The National Pork Producers Council, the National Milk Producers Federation, the National Corn Growers Association and Iowa State University have been urging the U.S. Department of Agriculture (USDA) to quickly establish a FMD vaccine bank to prepare for a potential outbreak of FMD in U.S. livestock, even though the last outbreak was in 1929.² Iowa State University and the Swine Health Information Center have played a central part in FMD research in livestock.³ The groups acknowledge that the USDA has taken some measures to create a vaccine bank; however, they are calling for the USDA to use funding included in the 2018 Farm Bill to purchase a large volume of vaccines to effectively contain an FMD outbreak if it occurs.

Zoetis and Texas A&M to Build Biocontainment Lab

Part of the agreement includes Zoetis setting up a 12,800-square-foot secure, biocontainment lab off-campus using modular cleanroom technology. The Trans-boundary and Emerging Disease Vaccine Development Facility is expected to open mid-2020 pending approval from USDA.
Scientists creating an FMD vaccine will receive FMD strains for the Zoetis FMD vaccine design that are believed to be non-infectious to cattle and other livestock. According to Dr. John Hardham, Research Director in Global Biologics Research and Director of the Zoetis Center for Trans-boundary and Emerging Diseases:

We are proud to be working with Texas A&M in the development of this critical vaccine to protect the health of livestock in the U.S. and markets around the world. FMD is one of the most serious diseases for livestock owners, and through an innovative vaccine platform, we can help them reduce the risk of an outbreak and avoid significant economic losses.¹

The Case Against Pre-Vaccinating

Typically vaccines are administered prior to an outbreak in order to “prevent” the disease from manifesting in the host; however, according to experts, pre-vaccinating livestock for FMD is not a viable option. Dr. James Roth, MD, a professor in the department of Veterinary Microbiology and Preventative Medicine at Iowa State University’s College of Veterinary Medicine explains that if a country declares itself free internationally of FMD but have vaccinated for it, then, as outlined in international animal health rules, there would still be many safety and health regulations to go through in order to export the product.⁴ He says that:

Countries that would import your product want to see a lot of data to prove that that virus is not circulating in a low level, so you have to do very extensive diagnostic testing to prove that even though you’re vaccinating, there is no virus infecting the herds.³

In addition, Dr. Roth has stated that it is not pragmatic to pre-vaccinate livestock for FMD because, “There’s 23 different strains. We’d have to use 23 different vaccines to cover all possible strains in the world.”³He maintains that it is logical to argue against pre-vaccinating for a virus that has multiple strains, given that it is difficult to predict the virus strain that may cause the potential outbreak.
Over the past few years, the failure of influenza vaccine for humans to prevent infection and transmission of type A and B influenza viruses has demonstrated the difficulty of predicting which influenza virus strains will cause disease in a given flu season.⁵ Public health officials admit that influenza vaccines fail to prevent influenza more than half the time.⁶ In most years, flu shots do not prevent the influenza because they do not contain the most prevalent influenza strains that are making people sick.³

New Test to Distinguish Vaccinated from Unvaccinated

In the midst of the recent dialogue on FMD in livestock, Iowa State University, on behalf of the Swine Health Information Center, has developed a lab test to differentiate between FMD vaccine antibodies and antibodies that come from exposure to wild type virus in pigs.⁷ The test still needs to be approved by the USDA for use but experts are saying this represents a big step forward in being prepared for future FMD outbreaks.⁴
According to the executive director of the Swine Health Information Center Dr. Paul Sundberg: “There are FMD vaccines that are available and should we get FMD in North America, those vaccines will be probably be deployed to help control and prevent the spread of the virus.”⁵He adds that:

That would lead to a conundrum if the blood from those vaccinated animals were to be tested for antibodies because the antibodies that will show up from the vaccine could look like the antibodies that could show up from a natural infection. The natural infection might result in animals carrying the virus long term. The vaccine would not and it’s going to be important to be able to differentiate those two.⁴

Dr. Sundberg explains that this lab test can differentiate between vaccine strain FMD virus antibodies and antibodies produced by the wild-type FMD virus. He states, “Thus we would be able to differentiate those animals and we’d know which animals are at higher risk of being further sources of virus to other animals, a real important distinction that we’ll need to have should we need to respond to an outbreak.”⁴
Although there are several questions that remain unanswered regarding wild type FMD virus, vaccine strain FMD virus and immunity to wild type FMD virus, this type of specific lab testing would help differentiate between the types of FMD infections in vaccinated and unvaccinated pigs during periods of FMD outbreaks.
There have been many outbreaks of disease in highly vaccinated human populations. Although the blame is always placed on unvaccinated individuals, there is a lot of evidence that vaccinated persons show few or no symptoms but can still transmit infections to other people,⁸ ⁹ and that vaccine strain live virus infections in those recently vaccinated can be mistaken for wild-type virus infections. An article published in the Journal of Clinical Microbiology in 2017 revealed that PCR testing was used to check measles case samples taken during the 2015 California measles outbreak.¹⁰Researchers found that about 40 percent of measles case specimens were identified as vaccine strain measles virus infections in recently vaccinated people, not wild-type measles, and stated:

During the measles outbreak in California in 2015, a large number of suspected cases occurred in recent vaccinees. Of the 194 measles virus sequences obtained in the United States in 2015, 73 were identified as vaccine sequences (R. J. McNall, unpublished data).”¹¹

Reference

Templeton Times

Monday, November 4, 2019