>The mRNA utilizes your cell's machinery to produce proteins
Does it? I thought the immune response was purely based on the free floating mRNA (which give a high immune response because that also happens during a highly active viral infection)
No: mRNA is the intermediate transcription stage of protein synthesis: mRNA molecules are synthesized from DNA in the cell nucleus, exit the nucleus and interact with ribosomes which synthesize proteins from them - there's also a suite of modifications and moderating systems (i.e. the short interfering RNA system which marks mRNA for destruction within the cell).
mRNA injections are based on the observation that with stabilisation, you'll get limited synthesis of an injected RNA strand by cellular machinery, and then the resultant protein will be presented on the cell surface - this is how the immune system detects active viral infections, since it's the same process: the virus dumps it's payload into the cell and gets its proteins copied up (+ an RNA or DNA polymerase to replicate the genome of the virus, which a vaccine does not have).
The magic of this process is that you don't have to handle bespoke proteins for new vaccines: you "just" change the delivered mRNA sequence, and use the same manufacturing line to make it, keeping the chemistry consistent and considerably simpler.
It's a refined version of attenuated or live virus vaccines, where you shoot the whole viral system in and it does the same thing - but then you've got to keep a bunch of custom proteins intact and you can't make it as easily.
No, the mRNA are templates for Covid-19 spike proteins, and the body learns to recognize (and develop an immune response) to said proteins.
https://en.wikipedia.org/wiki/MRNA_vaccine
Does it? I thought the immune response was purely based on the free floating mRNA (which give a high immune response because that also happens during a highly active viral infection)