Um, COVID comes with the spike protein. Along with the rest of the virus that replicates itself and its spike protein until your body learns how to fight it off.
Covid does come with the spike protien ... which it no longer makes after a covid infection has resolved. And that’s only if you get infected in the first place.
The nanoparticles with spike-protien-making mRNA, on the other hand, are going to be in the recipients for life, slowly eluting their contents until they run out. No one knows how long that running out will take. Could be years. Could be decades. Could be the rest of your life.