I have heard a lot of discussion recently about the desirability of some sort of "passport" identifying the bearer of such a document as having been Covid 19 vaccinated.
The travel industry seems to be hugely supportive of the idea.
Restaurants and bars seem to like it also.
Even the governments in charge of doing the vaccinations like the concept - what better way to slap down vaccine resistors than to implement a document that makes the recipients of Covid 19 vaccine able to become fully participating citizens again?
Israel has already come up with some green colored emblem of vaccination.
A couple of questions seem to recur: "how do we control counterfeits"? and "how do we make the carrying of such documentation easy to do and difficult to leave behind on the dresser at home"?
The answer to me is obvious (I am surprised that Bill Gates hasn't already suggested it): put a computer chip in each vaccine dose.