Or just that we can't stabilize/synthesize the protein usefully in a vaccine with existing techniques.
One of the big deals of mRNA is that because you get the proteins made in-vivo (in the body), you inherit all the body's machinery to do this naturally - after all, viral replication requires using that exact same machinery in order to replicate up the viral proteins in the first place.
One of the big deals of mRNA is that because you get the proteins made in-vivo (in the body), you inherit all the body's machinery to do this naturally - after all, viral replication requires using that exact same machinery in order to replicate up the viral proteins in the first place.