@freemo Having just received my second Pfizer vaccination yesterday morning, after my first one three weeks ago, I share many of your concerns (Interestingly, by way of an aside, why is the roll-out on this remote Greek island more efficient tha Germany or the UK?)
See:
Ten reasons why immunity passports are a bad idea
https://www.nature.com/articles/d41586-020-01451-0
Ironically, Symi only had one case of confirmed Covid until ten days ago (a Belgian tourist last September), but now a local family is in quarantine and all contacts are being traced. How did this happen? Because a policeman illegally visited another island. And the vector of transmission? Basket ball!