depending on the vacceine once they defrost them they only have a shelf life of i think 5 days. so i am not suprised at that.
my sisters volunteering jabbing people and they have a system for setting up days in advance, they know how many jabs they can do in a day and have that number defrosted 3 days in advance and they move alongg like a production line.
thats why you here of them slotting in extras when people dont show for appointments as the vacceine has limited life.
each day they do have a short call standby list of health workers etc that they can call to take up spares.