Compared to things like listeria or salmonella? Surely, you’re joking. E. coli is benign in most cases. For perspective, in France (since we’re talking about French cheese), the orders of magnitude are hundreds of deaths each year from salmonella, tens from listeria (with a death rate of ~20% for its invasive form), and even fewer from E. coli.

Except in a tiny number of cases it is unpleasant but short and not threatening (remember to drink a lot, though, the most dangerous effect is dehydration).