As far as I've read, Pfizer has created and is manufacturing, special dry ice boxes that can store the vaccine for a few weeks, supposing that the storage/distribution facility is replenishing the dry ice up to twice. This won't be a big deal for hospitals, as any hospital worth its salt has -70 to -80 freezers on double redundant backup generators. But it's unreasonable to think that only hospitals are going to be their distribution centers, so hopefully their custom dry ice boxes are sufficient (or they figure out how the hell Moderna did it, and add whatever stabilizers are necessary to raise the storage temp to -20). The thing about storage conditions, as I'm sure you know, is that they are what you define them to be, as dictated by the stability studies that you showed the FDA. RNAs are generally considered some of the most unstable biomolecules, so they are typically stored at -70/-80. It's possible that Pfizer, in all their haste to make a mRNA product, which they've never done before, just did stability studies at -70 and haven't completed any data on other storage conditions yet (they're long, expensive, and tedious). Moderna on the other hand, as their name suggests, specializes in mRNA product development, so their know-how in that space is bound to be vast. Considering that both vaccines are based on mRNA for the now famous spike protein, hopefully there will be some data sharing so that the best, easiest, and most widely available distribution will be possible. Hopefully, the feds don't mind stepping in and forcing data sharing if necessary, as is their right under IP law.