While people, especially in the US are fighting to prevent the federal government from bringing in the vaccine passports, what has not been seriously considered to the same degree of concern, is that there may still be vaccine passports brought in by the corporates, who effectively rule the modern worlds anyway. The private sector, such as airlines and even pubs will require some certificate to plat ball, and before you know it, a de facto vaccine passport will arise. Merely require it for things the great unwashed crave, like booze and sports, and people will accept anything, then it will be pushed for shopping, and Bob’s your uncle, the vaccine passport is in, easy. Here is some information about this.