Ubiquitin, I said no mohel does MBP with open sores, and intuitively, it definitely seems dangerous.
I don’t know if the two cases are comparable, though. There are plenty of cases in which people have fallen from high places and died without a parachute, and plenty of cases in which people have safely used parachutes. So we know that parachutes are necessary and effective, even without a study. Do we know for a fact that an open sore causes the transmission of HSV? Maybe we do; I don’t know, I’m merely asking.