It really depends on the quantity. The Pfizer vaccine has 0.3 ml per dose. Assuming the hoax story is 1/10th of that is graphene oxide, it is going to give the person a bad headache at worst.
This is like you eating almonds.
Almonds contain cyanide.
But in such microscopic quantities that you’d need to eat kilos of almonds to get sick
The best initial approach to any information these days is skepticism.
Doubt or outright disbelief is warranted when the information comes from the establishment.