I don’t have a problem with someone wanting a known blood supply.
But if ‘known supply’ doesn’t match type - and you’re desperate - I don’t think you’re going to worry about ‘spike proteins’.
The point that I am attempting to take is that the blood and plasma industry does not and cannot know every disease and pathology in the blood of donors. Limiting your exposure to risk is a human right and medicine had better get its head on straight or they will lose a lot of money.
What are the implications of a young girl getting a blood donation from an old man? Will she age faster over her lifetime due to the old man’s stem cells colonizing her bones? Will she develop an odd interest in motor sports?
Nobody knows.