From what I read about this part

Yet the cells have been engineered using mRNA to produce these spike proteins. If you research this I'd be interested to find out what mRNA tech they have come up with that has a timed limiter on it.

MRNa doesn't live longer than 24 to 48 hours when injected into you, it does go somewhat past the blood brain barrier they do admit, and there is some small amount of radiation or something that happens but it's supposedly negligible.

Can't remember where I read that weeks ago, but it seems to have made sense.