> if you have a documented recovery from infection, you are also granted an immunity card ... I don't know how many other countries are using this approach.

I think most European countries do. I know for certain that the UK does[1] as well as Germany[2] and Austria[3].

[1] https://www.nhs.uk/conditions/coronavirus-covid-19/covid-pas... [2] https://www.baden-wuerttemberg.de/en/service/aktuelle-infos-... [3] https://gruenerpass.gv.at/genesen/