Please clarify.
If, as advertised, this drug is 100% effective the answer to the question should be Zero. If there is any other answer we might want to reconsider.
If we knew that, it might tell us something about how effective it is. The problem with that is that it probably wouldn’t tell us much about how effective it is for people without preexisting conditions because if people were already on it, they’re on it for some reason.