A challenge with vaccination certificates is to make sure they are genuine.

Then you must be able to trace back to the time of vaccination with information about who gave it, when and which vaccine was given.

But then the problem arises to make sure that all this patient data does not end up in the wrong hands.

And should people from poor countries not be able to travel because vaccines have not been available?

Hear SVT's tech correspondent Alexander Norén about three dilemmas governments face before vaccination passes are introduced.