To understand just how stupid this claim is, the guy making it claims he was given this 80% number by a right-wing antivax former-MP who was expelled from the Conservative party for making false claims about the vaccine.
Furthermore, the author (Steve Kirsch) then went on to ask AI models "what this means" - this is a parfait of stupidity.
https://kirschsubstack.com/p/if-the-covid-shots-are-so-safe-then