The vaccine matters, as they have different storage requirements and dosing requirements. One of the vaccines requires that it be kept in a deep freeze, thawed

The vaccine matters, as they have different storage requirements and dosing requirements. One of the vaccines requires that it be kept in a deep freeze, thawed before use, and everyone needs two doses. This is a logistically complicated process that takes much more time to deliver, and will therefore be slower. The Oxford vaccine can be stored in a regular refrigerator, which drastically reduces infrastructure cost and makes it speedier to administer, since it doesn’t need to be carefully warmed to room temperature from subzero. Oh, and it’s cheaper. That matters.