There haven't been any other mRNA vaccines at all. This is the very first one, and on an accelerated schedule. So the answer to your question is unknown, and

There haven't been any other mRNA vaccines at all. This is the very first one, and on an accelerated schedule. So the answer to your question is unknown, and whoever goes first gets to be part of the large study answering that question. Personally I'm going to wait for either a conventional vaccine, or at least a year or so by lots of other people. (It helps that I'm 90% sure I had it already, and I'm low risk on top of that.)