[q1w2]

This is wrong in two important ways.

1. The vaccine does not stay in your muscle - obviously. It spreads out from the muscle slowly and does indeed enter your blood stream.

2. It is not put spike protein. It is an exposed spike protein on a larger stable "base" that ensures the spike doesn't degrade easily - so while it's smaller than the virus, the entire vaccine protein is significantly larger than just the spike.

[rrock]

There is no spike protein in the vaccine. There is mRNA. That mRNA needs ribosomes to make the spike protein. So think about where there are ribosomes, and where the protein is made, and you’ll find the correct answer.

I don’t know where you heard the second point, but it is equally incorrect. The mRNA encodes just the spike, with two mutations to lock it into a pre-fusion conformation. Nothing there that qualifies as a “larger stable base”. The sequence is found here: https://web.archive.org/web/20210105162941/https://mednet-co...

[q1w2]

You see the poly(A) sequence at the end? That is what stabalizes the entire structure so that it doesn't denature. I called it a "base", but you are right that it's not adding to the size of the overall structure much.

The point is that the normal virus protein obviously doesn't have that - it's human design to create stability.

My point was that there are not billions of covid spike proteins floating around the human body when you get the vaccine.

[rrock]

The polyA tail is in the 3′ UTR (after the stop codon) and is not translated. It doesn’t appear in the final protein sequence. It’s also a fairly standard feature.

[q1w2]

To be clear, it's not translated into the final antibody, but it remains present in the vaccine, and hence in your body - it is what gives the vaccine structural stability in the body.

...and yes, it is standard - it is not covid-vaccine specific.

This is all covered in This Week in Virology - one of the recent episodes about 3 months ago.