The Moderna shot had more relaxed requirements from the beginning, and the Pfizer shot could be stored for a month by adding dry ice to the shipping container.

The Moderna shot had more relaxed requirements from the beginning, and the Pfizer shot could be stored for a month by adding dry ice to the shipping container. There was focus on the requirements, but there were lots of people arguing that they weren't that onerous for wealthy countries (and they aren't particularly onerous).