They already did, that was done before they launched the vaccines. You still don't think they are safe, so now it is up to you to prove why. Which you can't, because you have nothing but your feelings to show for it.
They did but it was an abridged version shall we say. Which is fine. It was an emergency and the law foresees this.
But the cultural shift towards harm avoidance at all costs and general authoritarianism (as clearly on display here on this site) led governments the world over to, use heavy handed tactics, shall we say, to get people to take it.
I am absolutely not against the vaccines. I got three doses of Pfizer. But I am profoundly against the heavy handed tactics used in deploying them.
They completed all of the normal testing. The mRNA vaccines technology is decades old. They did all of the normal testing but the stages were done in parallel and pushed ahead of everything else in the pipe. Had any stage failed the approvals would not have been given. This is an anti-vax meme but it is completely false.