[Question] Would Covid19 patients benefit from blood transfusions from people who have recovered?

Epistemic sta­tus: wild idea thrown out there in case it is brilli­ant.

Pre­sum­ably, the blood of re­cov­ered pa­tients has some an­ti­body that tar­gets the virus. Blood trans­fu­sions are widely un­der­stood and known safe. (Or at least safe so long as you don’t do a few things that doc­tors know not to do, like giv­ing AB blood to an O pa­tient. ) Is it an­other thing that should work in prin­ci­ple, is more likely than not to work in prac­tice, but by the time some­one has run the med­i­cal trial, it will be all over. Of course, the re­cov­ered pa­tients blood con­tains enough an­ti­bodys to make them im­mune, but I don’t know how big an effect a frac­tion of the con­cen­tra­tion would have. Of course given ex­po­nen­tial growth rates, there might be far more crit­i­cally ill pa­tients than re­cov­ered pa­tients. It might be pos­si­ble to sep­a­rate the an­ti­body from the rest of the blood, or even grow it by in­fect­ing cells with covid19 in a lab.