the "however" I know you're expecting ;-)...
The mRNA vaccines, while new, are the result of research going back decades by thousands of talented and knowledgable investigators from many related fields...plus they utilized "standard procedures" for testing and evaluation before gaining approval for production/distribution...with voluminous tracking methods being employed as we speak.
The incredible benefits that this technology provides are a quantum jump from where we used to be...much faster response to new pathogens, plus the ability to rapidly adjust and 'tweak' the product as problematic variants emerge. Any rational decision maker would do what has and is being done, given the alternative of waiting 'a lifetime' for proof that the technology had absolutely no uncertainties and suffering the obvious consequences...you getting one of them shows you to be one of those types.