You cannot know the long term effects (decades) of a solution that is younger than decades.
You can: it's the same solution than the ones that have been used in other mRNA vaccines, used for pets as general vaccination against some illnesses for over 15 years, and a few clinical studies in humans beforehand as well. Only what they make the body produce changes, based on a different organisation of
one of the components, and what they produce we know very well: they only make the body produce antibodies.
Get your goddamned facts straights, tabzer, please.
At this point it's like saying "I'm not eating this chocolate because the brand I don't know and it has not been on the shelves for 10 years so I don't know the long-term side effects because it's organised and packaged differently than the one I'm used to". It's at best useless, at worst (when making unfounded claims about it) dangerous because people will listen far easier to the fear you instill in them than to actual facts. And people far worse than you know and use that, they have been doing so for years. And thanks to people like that, we're seeing surges of illnesses that had been almost eradicated, because of people not getting their frigging vacccines as
preventative measure, like it's meant to be.