You say this as if it is established fact, but there has been no RCT convincingly showing the effect you are describing - typically called "source control" - can be achieved from the use of a respirator to interdict individual transmission. In fact, no RCT powered for such a finding has even been attempted to my knowledge (though I haven't combed through the research in the past couple months or so - link me if I'm out of date!).
It has also not been demonstrated that source control can be used to reduce community transmission (though I realize that your point is not about community transmission).
The reasons for not funding / performing such a RCT continue to astound - the demagoguery of comparing masks to parachutes notwithstanding.
It has also not been demonstrated that source control can be used to reduce community transmission (though I realize that your point is not about community transmission).
The reasons for not funding / performing such a RCT continue to astound - the demagoguery of comparing masks to parachutes notwithstanding.