Here in Canada, it appears that we'll have vaccine passports, at least for the time being (i.e., to be repealed if/when the COVID narratives fully collapse, vaccine dangers exposed).
These will use QR technology it seems, if the following stories are any indication.
Quebec:
Whistle-blower out of Manitoba:
This might have some functional issues (i.e., not everyone has a smart phone), in which case, I would assume they would require paper copies.
Someone on another one of the .win forums made a good point about vaccine passports though, the point isn't functionality, it's obedience/conditioning.
If/when vaccine passports comes to some states in the US, wouldn't be surprised if they go down a similar path of using QR codes.
QR code basically equals bar code. You are cattle to be counted herded and eventually culled