It tends to 'degrade' from the end, which is why all of the additional 'A' nucleotides are tacked on to the end, it's basically a NOOP sled that gets shorter an

It tends to 'degrade' from the end, which is why all of the additional 'A' nucleotides are tacked on to the end, it's basically a NOOP sled that gets shorter and shorter until the instance is disabled. The mRNA isn't intended to be copied in the body. Once the dose is used up there should be no more spike proteins created.