Probably not. There was about 20yrs of research on using mRNA for gene therapy before the CRISPR/Cas9 discovery. It was abandoned as a route for gene therapy specifically because it wasn't long lasting. The mRNA isn't incorporated into the DNA, so it isn't reproduced by the cells and eventually breaks down. Things inside of cells are flying around at high speeds and constantly colliding, so it's not a very stable environment.
There are people that this was tested on still hanging around with no lasting negative effects (to my knowledge).
There are people that this was tested on still hanging around with no lasting negative effects (to my knowledge).