DNA resides in the Nucleus of a Cell. mRNA does Not penetrate into the Nucleus of the Cell or have any effect on DNA which some misguided medical people seem to think, but they are wrong. mRNA has been used in many Vaccines long before now, including some Flu Vaccines. There is nothing wrong with mRNA. I got the pfizer vaccine Tuesday.
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html#:~:text=COVID-19 mRNA vaccines are,and gets rid of them