Early delivery, or mutually agreeable variations will be written in. If you look at the ABC's jab progress charter, you will see countries vaccination rates seem to flatten or peter out before 70% like Canada and Israel. I hear USA is swimming in unused vaccines. They are at only 55% odd, and that's not because of lack of incentives. And in some places, there is drive-thru Moderna shots, 3 minutes and you are done. Given by unpaid volunteers who had 1 hour of training.
Sseeing that we are great allies and buddies of the US of A, can't our PM Scomo just pick up the phone to President Joe ask ask him to send us a few million doses of their unused vaccines? After all, we willingly followed them into their wars when they asked us to. So I don't see them saying no to us asking for for a few millions doses of their spare/unused vaccines.