The ignorance...
FYI, the mRNA vaccine isn't "new", we've been studying this technique for almost 30 years, and it's been deployed to fight cancer several times.
In the case of the Biontech / Moderna vaccine, it's also not new, but was developed to fight the original SARS 10 years ago. But if that still bugs you, fine... just go get the Johnson and Johnson shot, which is based on utterly different tech and uses technology similar to the flu shot.
And yes, the mRNA vaccine is "safe", it's the safest vaccine technology we've ever invented as a species. But I understand the ignorance, because unless you've got a chronic illness in the house that forces you to stay up on this junk you'd never know any of this. I know about it because mRNA therapies are one of the most promising angles being explored to end type 1 Diabetes, the chronic illness I have the joy to deal with. But it's also being used to fight cancer on a level that's near miraculous too.
But again, the only reason these mRNA tools have made it to the shelf so soon isn't the emergency authorization. It's because they have been tested and trialed over the last DECADE not the last year. Otherwise the FDA one of the most conservative medical bodies on the planet never would have authorized them. Not when Johnson and Johnson with more normal technology was days away too.
But please do talk to your doctor, because the one risk the mRNA vaccines have is an anaphylactic reaction, that mirrors what happens to people allergic to peanut oil. If you have another oil based allergy of any kind, I'd be using the J&J shot! But talk to your doctor, because there's no sense in just getting one at random, you've got a choice of an entire cocktail of options now.