Hopefully you don't need surgery, but things happen and you might need a transfusion. Getting someone else's blood is always a little risky. And now you don't know if you're getting blood from someone who has been vaccinated. Perhaps you didn't want the jab, but in the event of a medical emergency, who knows what you'll be getting.
The American Red Cross reports that 20% of donated blood has COVID-19 antibodies
I think you can ask for Plasm only. I think that is what Jehovah's Witness ask for instead of a full blood transfusion. But I could be dead wrong.
I grew up a Jehovah's witness, can confirm that they consider using plasma only on a "basis of conscience" because the underlying command is to abstain from blood from the Old Testament. Done take it to the most fundamental and refuse all transfusion
From what I know, they have surgery setup well in advance with a machine that cycles their blood and minimizes the loss by pumping it back to them, almost always choosing alternative methods such as laproscopic and minimum invasion techniques, there have actually been several historic lawsuits involving parents of Jehovah witness children choosing religion over life for their children, and some with doctors infringing on their religious rights by giving their children blood and blood products during emergency life-saving procedures. I worked in blood banking as a career, and last I checked they still were refusing any blood products, but it's been over a year since I retired.
The JWs now use a synthic blood dibstitute.. not sure whats in it... it works apparantly
I was just talking to a surgical nurse friend, and they don't even use plasma.