Thank you very much for the question.
The two departments, CFIA and Health Canada, actually get involved. The vaccine you're talking about was produced by a Canadian company. What it does is reduce the shedding of E. coli in the feces. It is one tool that can be used in the overall arsenal to try to reduce the load of E. coli 0157 in the food supply.
From what I remember, some of the difficulty is in showing the public health benefit of this. For example, with the use of this vaccine, can you actually show that you've had a reduction in the number of cases of E. coli 0157 in the human population? That is quite difficult to do because of the complexities of the system.
I agree with you that it is a good tool, but it is just one of the tools. There are other things that have been used—for example, bacteria flushes—to inactivate cells of E. coli.
So it's a good tool and one that can be used, but its efficacy in reducing the burden on public health due to E. coli 0157 is very difficult to ascertain.