mRNA vaccines are not new, they have been under development for over 20 years. It's just that they don't work. Also the spike protein doesn't always stay in the muscle tissue, but can escape and float round the body, before settling in important organs. There is no research or information on the effect this will have, but it is certainly not beneficial.
I understand how they work, and they are a step closer to the use of the live virus. I just don't understand why they don't use the live virus to create natural immunity. Oh wait, there isn't any money in that.
You don't understand how vaccines work.
After vaccination, the cells make copies of the spike protein, and the mRNA is degraded within a few days and the spike proteins last only up to a few weeks.
https://www.muhealth.org/our-stories/how-do-we-know-covid-19-vaccine-wont-have-long-term-side-effectsUnderstanding How COVID-19 Vaccines Work -
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html