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Why Aren’t We Using Vaccines for E. Coli O157:H7?

For those who have been working on food safety for years — even decades — the promise of a quick-fix holds no allure.  Experts know that food safety is multi-faceted, and no silver bullet exists to wipe the scourge of E. coli 0157:H7 from existence.  But where promising new technologies could — in combination with common-sense approaches — make serious contributions to public health, they should be advanced.  Pre-harvest vaccines for E. coli O157:H7 could very well be one of them.  So why aren’t we using them?

At least two promising vaccines for E. coli O157:H7 are awaiting licensing approval from the Center for Veterinary Biologics (CVB) at APHIS.  CVB has a long history with animal vaccines, but has primarily focused on those that improve animal health — not human health.  The E. coli vaccines under consideration are not designed to prevent illness in the animal, but could significantly decrease the amount of the pathogen present in the pre-harvest environment, and presumably in the meat that winds up on consumers’ plates.  Vaccines focusing on public, rather than animal, health represent fairly new ground for the agency.  Given the delays in their approval, CVB may be having trouble adjusting its vision.

  

In a series of conversations with many of the players involved — representatives from CVB and the pharmaceutical companies awaiting licensure — CVB’s approach has been striking.  Far from being enthusiastic about the public health possibilities of pre-harvest vaccines for E. coli, the agency instead seems beleaguered and adrift on the issue, even admitting in one conversation that although there’s no scientific downside to the vaccines, there are some economic and practical issues to consider.  Perhaps there are economic and practical issues to consider — but that’s not CVB’s mission. The fiscal implications and logistical applications to these vaccines are issues for the free market to deal with, and not reasons to delay licensing of promising new technologies that could make a significant public health impact.

  

The key issue for CVB — indeed, the only issue the agency has authority to consider — is whether the vaccines are pure, safe, potent, and effective.  In meetings with CVB officials, the agency acknowledges that the vaccines under consideration have cleared the first three hurdles.  It’s the efficacy that appears to be tripping them up.  CVB says that the industry wants an expectation of efficacy that would decrease summer E. coli shedding rates in cattle to approximate winter shedding rates, an efficacy of between 55 and 65 percent.  This is a laudable goal, and it’s useful to know what the industry would like to see from a new pre-harvest tool to combat contamination.  But surely the Food Safety and Inspection Service (FSIS), the agency whose mission is to ensure the safety of meat for consumers, has an opinion on whether that expectation of efficacy is too high, too low, or just right?  Unfortunately, CVB doesn’t know it.  From what we can tell, CVB has a bold new responsibility to consider vaccines with a possibly significant public health impact, but they haven’t taken steps toward a meaningful collaboration with the relevant public health agency that sits in the same building to decide how best to exercise that power.

  

How CVB came into its responsibility for vaccines that have a public health focus (rather than the traditional animal health focus) is somewhat mysterious.  Perhaps it was simply that the agency was left without a chair when, in the early 2000s, the music stopped on a debate about where to house these types of animal vaccine approvals.  True or not, the agency has entered a new era — one where their focus on animal health must share the spotlight with a commensurate consideration for public health.

  

It’s time for CVB to embrace that new responsibility, first by re-focusing on its actual statutory mission and away from tangential issues of practicality and economy.  Second, the agency must consult with FSIS and gather the relevant stakeholders to discuss how vaccines can make a contribution to public health.  Third, CVB should streamline and make more transparent the entire process of vaccine approval, so that interested parties can follow the progress — or lack thereof — of promising technologies under consideration.

There’s no guarantee about these vaccines, but even without a silver bullet, it is possible much progress can still be made.  CVB has the authority and the responsibility to put yet another tool in the box to fight the scourge of E. coli.  Now the agency must rise to meet its new public health role, by streamlining, prioritizing, and publicizing the vaccine approval process for those technologies that could have a significant impact on public health.

Here’s a letter written by the Center for Science in the Public Interest to USDA Secretary Tom Vilsack about the delay in vaccine approvals.

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Sarah A. Klein, J.D., M.A. is Staff Attorney, Food Safety Program, at the

Center for Science in the Public Interest

© Food Safety News
  • Dan Cohen

    Michael Jacobson’s letter, from the Center for Science in the Public Interest, is worth reading.
    There is some irony in the fact that public health advocates have to argue for the efficacy of the free market in economic decisions, as well as for the efficacy of actual scientific evidence in scientific judgements.
    A worse case was the USDA’s suing to stop Creekstone Farms Premium Beef, in Kansas, from testing all its animals for bovine spongiforn encephelopathy (BSE, “Mad Cow”). USDA asserted an authority to prevent the sale of both scientific testing kits for BSE and, in addition, preventing the sale of meat where a claim of having tested each animal was made, the whole point of Creekstone’s testing. In a split decision the US Court of Appeals for the DC circuit found that the USDA HAD such authority for banning test kits under the same VSTA law mentioned above (see Food Law Blog). I think the whole case was still unsettled 8 years later, and Creekstone is now owned by Sun Capital Partners.
    To a non-legal observer, the USDA appears to have pulled its asserted authority from deep within its bureaucratic bowels. When I was growing up there were many common sayings that appeared to be truisms like “the customer is always right”. In this case the customer was, so to speak, Japan.
    If I remember the early test herd data correctly, both vaccines for O157:H7 reduced shedding, but not enough to be a magic bullet. Nor, that I can recall, would the vaccines be effective against other STEC. But they could provide one more tool in the overall management of O157:H7 in CAFO’s in particular. So it shouldn’t be up to the USDA to prevent this tool from being available.
    On the other hand, CVB has managed to permit multiple horse vaccines for west nile virus, for years, while no vaccines are available for humans. So they can be efficient when they are motivated.

  • http://www.johnmunsell.com jmunsell

    Dan Cohen’s remarks are spot on. Preventing the use of vaccines because they are not the 100% effective silver bullet cannot be justified. Beef slaughter plants currently have a variety of pathogen interventions in place, none of which are a silver bullet………but FSIS still allows their use. Vaccines should be one more intervention in our portfolio because it does add an additional layer of protection to consumers.
    John Munsell

  • cookson beecher

    Two quick responses to Dan Cohen’s comments:
    First off, I think we all went into shock when the USDA told Creekstone Farms that it couldn’t test each of its animals for E coli. It seemed to be the opposite of what the agency should be doing both for the health of consumers and the financial health of a company.
    Secondly, one time when I was doing an article about West Nile virus, I asked a veterinarian why a vaccine for horses had been developed but not one for humans. He told me that some horses can be worth millions of dollars and the horse industry wanted to protect the value of those horses. As a result, it put a lot of money into developing a vaccine against the virus. After all, you don’t want to spend tons of money on a horse and have it keel over dead from the virus. As for us humans, well, we’re valuable to one another but, as it turns out, not as valuable as some horses are to their owners.

  • Brian Honigbaum

    Creekstone asked USDA to test each animal for BSE, not E. coli.

  • Gentle Reader

    Cookson – You are confusing BSE with E. coli. You also are confusing vaccine efficacy with wishful thinking. Finally, you conflate your confusion into righteous indignation. How embarrassing for a journalist.

  • cookson beecher

    Thanks for the clarification Brian. My error to be sure. Yet, the principle is similar in terms of what USDA’s job is.
    As for Gentle Reader’s comments, thanks for “ever so gently” exposing me in the act of “conflation.” Hey, it happens to the best of us . . . and the worst of us. Sorry about that.

  • doc raymond

    Good piece, Sarah, and many agree with you about the need for APHIS and FSIS to work togther more effectively. For your information they did receive a chastisement from an irate Undersecretary for Food Safety in 2007 when he found out they had no plans to advance these vaccines because they were not 100% effective.

  • http://www.johnmunsell.com John Munsell

    Dan Cohen’s remarks are spot on. Preventing the use of vaccines because they are not the 100% effective silver bullet cannot be justified. Beef slaughter plants currently have a variety of pathogen interventions in place, none of which are a silver bullet………but FSIS still allows their use. Vaccines should be one more intervention in our portfolio because it does add an additional layer of protection to consumers.
    John Munsell