A Covid Vaccine

seems to be to be something of a fantasy, because
it has to be delivered (very expensively) to sceptical populations, and,
having been delivered, will, for the purpose of free movement,
have to be attested (like a cholera or yellow-fever inoculation)
by a document which will be relatively easy to forge...
unless each vaccination is accompanied by a tattooed number
(harder to phony-up) which will remind a few of us of
concentration-camps and totalitarian régimes,
or by some sort of electronic tag
(maybe like a credit- or health-insurance card with PIN)...
Ah dear Covid!  amuse-bouche or hors d'œuvre 
of our future - you have come not a moment too soon.