The science and history of the mRNA is honestly so cool. It's a shame some believe there's arbitrary risks that somehow they're aware of but not the actual medical professionals that created and studied this stuff.The "long term consideration" is a VERY common theme originating with the anti-vaxx movement many, many years ago. mRNA vaccines have been in development for decades.
ETA: To clarify...the only reason we've never had an mRNA vaccine approved before is because there weren't enough people getting sick at the same time to perform trials. COVID provided enough patients for trials to occur.