The debate about whether there's enough to justify calling mRNA vaccines "safe" yet reminds me of the microwave oven.
After the microwave was invented, they started going into restaurants, and then home versions were created, and they started going into everyone's kitchens, too.
Now, they did some looking at the short-term effects of microwaves, but, they couldn't really do a study on "What happens when you expose yourself to 3 minutes of radiation every day for 30 years when you heat up your coffee?" without, you know, waiting 30 years to run the test. They looked at the short-term, figured it was safe enough, and that long-term probably won't matter.
Now... well, I'm betting you have a microwave in your house. Or, if not, you're at least not actively avoiding microwave ovens, are you? You're not thinking "Man, the science on the 30+ year long-term effects of these things isn't settled, I don't trust it", are you?
Same with mRNA. We know the mechanism it works through. We can measure the short-term impact enough to judge the long-term implications. We don't need to actually wait 30 years to start using these things like we didn't wait 30 years to start using microwave ovens. I get people feel the J&J is like a dorm room hot plate and that might be good enough. Fine. But I'll think I'm OK making this popcorn in the microwave just fine.