It is actually a difficult thing for Biden to manage. And I can see over the last couple of days Biden has stepped back a touch.
By all rights Biden should be saying "This is what you get when you're an idiot who ignores medical advice... Who would trust Trump man to give them medical advice when he can't even follow his own scientists advice..." etc etc... really hammering it home... But he can't because it makes him look like a mean old man.