They will not allow it. Their doctrine states that plasma is a major blood fraction, and is therefore forbidden to give or receive even if lives are at stake. The ones that give or take this blood fraction could probably be threatened with being destroyed by joke-hova, since they are supposed to suffer all the more and be willing to die for that worthless piece of trash.
I would like to see the members of the Filthful and Disgraceful Slavebugger get coronavirus and need this treatment or die miserable deaths (not easy deaths, either). They expect those in the field to surrender to dying, yet I would be willing to bet that they would take blood plasma if they got coronavirus. And they would lie about it, which is to me far worse than doing the blood.
As I see it, that is one more treatment option, albeit a quite expensive one. (Blood is highly perishable and is usually quite scarce.) There are other alternatives I would use before resorting to this. Vitamin and mineral supplements are good--I already take the vitamin C and zinc that is so hard to find these days. (I stock up to roughly 2 years' supply against these things becoming illegal, not just for the virus.) Schisandra berry, elderberry syrup, astragalus, and vitamin D (which is still quite available in most areas, where it is still legal) are good to take regularly. I also have oregano oil and echinacea on standby if I do catch the virus or get significant exposure to it. (And there are other herbs that help--you do have options.)
Beyond that, before the plasma, I would look into other drugs. Chloroquine is one example. That, combined with zinc, will wipe out coronavirus within 5-10 days. (Though chloroquine is dangerous for heart patients, and I do not advocate taking forms of the drug that are meant for fish or animals because you will get the wrong dose and may die from it).
I wonder how many of these other options the jokehovians have banned, either explicitly or because they cannot afford it or do no research on it. How many of them even take a vitamin pill? Myself, I started taking vitamin C to ward off dental abscesses, only to find it significantly reduces the chance of my catching colds. (And no one else caught on.)