A part of my job that I like is the fact that “it depends”. That's one typical answer I give to individuals. The strain of E. coli is one factor; the health status of the individual is another factor; the dose the individual gets is another factor. So there are lots of combinations of those factors.
You could check at CDC. I don't think we have a statistic on this in Canada, but I do go to the CDC for data. I do teach a course on biosafety at U of T, and I show different examples of lab-acquired infections to the attendees. As I mentioned, there are lots of them all the time.
The consequence would be different. If someone is immune-compromised, or let's say someone is pregnant and walks through a room and is exposed to listeria varicella, they would most likely no longer be pregnant after that. So that is a consequence. Is it a big consequence, or a small consequence? You be the judge. It's really hard for me to say, but that is one example.