My understanding of the mRNA process was that the spike is constructed and then "displayed" on the cell membrane; and the subsequent immune response will then flag and kill the cells.

Is it known whether in addition to "displaying" spikes, they also are in some cases produced and just ejected into the body? Can it be isolated in a blood draw post-jab?

Does each mRNA strand serve as a template to make a single spike or do they persist and keep producing many copies?