According to a press statement by Bioniche Life Sciences Inc., the two articles in the Journal of Food Protection relate to field challenge studies conducted at the University of Nebraska-Lincoln involving close to 900 animals in 2002 and 2003.
The first article, “Efficacy of dose regimen and observation of herd immunity from a vaccine against Escherichia coli O157:H7 for feedlot cattle” (R.E. Peterson, T.J. Klopfenstein, R.A. Moxley, G.E. Erickson, S. Hinkley, D. Rogan, and D.R. Smith), supports the hypothesis that use of the Bioniche vaccine effectively reduces the likelihood of cattle shedding E. coli O157:H7. After a three-dose treatment, vaccinated cattle were significantly less likely (73%) to shed the organism than unvaccinated cattle (P<0.0001). The same study noted that there was no indication of affect on (feed conversion) performance or carcass quality, and that vaccinating a majority of cattle within a pen resulted in a significant protective effect to unvaccinated cattle in the same pen. This effect is called “herd immunity”.
The second article, “Effect of a vaccine product containing type III secreted proteins on the probability of Escherichia coli O157:H7 fecal shedding and mucosal colonization in feedlot cattle” (R.E. Peterson, T.J. Klopfenstein, R.A. Moxley, G.E. Erickson, S. Hinkley, G. Bretschneider, E.M. Berberov, D. Rogan, and D. R. Smith), highlights the results of a study that looked at the effect of vaccination on the shedding of E. coli O157:H7 by cattle and their colonization by the organism. Vaccinated cattle were 98.3% less likely to be colonized by E. coli O157:H7 at the terminal rectum (where the bacteria are known to collect and reproduce in large quantities). Specifically, the authors were able to isolate E. coli O157:H7 from only one of 140 vaccinated cattle, versus 38 of 141 non-vaccinates (P<0.0001).