Chat about Novel Coronavirus - 2019-nCoV - COVID-19

They can only approve it for the way it's been trialed and tested, and they've trialed and tested this vaccine in a way that gets it to the public as quickly as possible whilst being safe, to do that they've not studied how effective it is to wait longer between doses because then they'd have to wait longer between doses to test it and it won't be given to people whilst that's happening. They can only approve what they have tested, using it differently may not be worse, may be better, but isn't trialed and tested so is outside of approval. Some people who are good at these things seem to think that based on previous experience using it in such a way may not be worse than the time restrained testing for each individual and may be better for everyone and therefore each individual, if longer gaps are used and more people get first doses sooner.