I don't think that is accurate. The spike protein that is being expressed has been modified (2p mutation) to enhance its stability. Proteins have a structure-fu

I don't think that is accurate. The spike protein that is being expressed has been modified (2p mutation) to enhance its stability. Proteins have a structure-function relationship and I believe this change in structure was done to inactivate the function of the spike protein, and merely use it as a immunogen. But I was making a different point. Even before you get to the final expression of the protein, there are various steps that need to go smoothly. The mRNA sequence is carefully engineered to dodge the body's various defenses, among other things - and this sort of engineering is not trivial - which is the point I thought you were also making with - "and the hardest part of developing new mRNA vaccines is to research the genetic code to put in it. ". But maybe I misunderstood your original point?