Another vaccine question

[garlictwist]

When you book your second vaccine, does it know which one you had for the first and only offer you venues that can offer you that vaccine?

Otherwise how does it know and is there a risk you won't get the same one?

Yes the system knows.

I had Moderna and wanted to change my 2nd appointment time and it only showed me 4 or 5 available venues as Moderna isn't widely available. The system will also know for AZ and Pfizer of course.

Yes, the system knows.