ok, i got distracted a bit, they started studying mrna in the 1960s, moved on to in vitro tests in animals in the 70s, and first tested them on people in the 90s. the corona vaccine is the first large scale use of them...
they've been researched since the 1960s, though, so it still answers your original statement, ( willing to have un-studied Mrna particles injected into thier bodies. )...they've not only been researched, they've been researched quite a bit for over 50 years. it seems that the only real problem with them was that all the applications they were good for already had accepted vaccines that were in production by pharmaceutical companies, who had no desire to develop a product to replace something they were already producing.
with the new use of them, and the associated research, they're now excited about using them to treat hiv, herpes, cancer, and several respiratory viruses...
so, say what you will, i'm entirely comfortable taking the vaccine, and plan to keep on doing it till the virus mutates into a new strain of flu, then i'll probably get a yearly shot for that, and never think about it doing me any harm...because it doesn't.