The main problems currently for any wise Government is that early in the vaccination program.Issuing vaccine passports are and in order of importance
1.If they issue passports such no doubt will lead to conspiracy theories exploding along with the resultant subsequent less take up of vaccine.
In order for a vaccine to be fully effective you need a minium of 95 % take up
2.Given ongoing emergence of new strains
Insufficient data to date to evaluate efficacy and does it suppress transmission
3.Quite simply Governments must agree a strict protocol jointly if issuing vaccine passports
Other wise a tower of babble created
Just look at your own travel passport
Other than holder,nation of issue,expiry and issue date and unique number
All other passports are Identical