[BostonCard]

This is an overblown "problem".  The reason you do a randomized, controlled trial is that a patient on hydroxychloroquine has an equal chance of landing in the treatment arm as in the control arm.  If you do it properly, roughly the same proportion of patients in each arm of your trial winds up having had HCQ so the effect evens out.

BC

[BostonCard]

This is an overblown "problem".  The reason you do a randomized, controlled trial is that a patient on hydroxychloroquine has an equal chance of landing in the treatment arm as in the control arm.  If you do it properly, roughly the same proportion of patients in each arm of your trial winds up having had HCQ so the effect evens out.

BC