This raises an important question:
Is this guy a plant by the authorities to make legitimate criticism of vaccine side-effects look like a kooky conspiracy theory? Or is he just a useful idiot?
Neither one. He’s quite knowledgeable but is extrapolating from animal viruses / vaccine’s.
Look up “Marek chickens” for more. Vaccinations for a certain virus in industrially raised chickens resulted in an arms race between the virus & immune systems of the chickens; the upshot was that extremely virulent forms of the virus emerged which kinda made the jabbed chickens sick but killed the others.
If you really want to give yourself nightmares, I can post to some other sites which discuss the suggested similar situation in humans due to selected mutations in the receptor binding domain of the virus, mainly omission of sulfur-containing amino acids IIRC.