I should imagine that such blood would no longer have the...

I should imagine that such blood would no longer have the ability to alter our DNA unless they had another booster just before giving blood and the DNA parcels were still in transit in the blood. It would contain the spike proteins though, along with their ability to damage the blood vessels and cause clots.

If the choice is the transfusion of tainted blood or death the transfusion would still be the better choice but you would need to go to work afterwards to get rid of all the crap before it did too much harm. They should mark the pure blood so that it's available for the people who passed the global IQ test.