Found this when discussing safety issues with the vaccine with someone who was arguing that Phase 1 weeds out any side effects, so waiting on all trials to finish was meaningless (it's not, as we can see here). He was arguing that FDA taking so long on approval is just because of bureaucracy (it is probably part of it, but all safety testing taking years is a big component of it).

I have heard this argument online which I believe is probably a Shareblue talking point on forums to try to shame people into taking the vaccine "there aren't any vaccines that have long term damage, all side effects occur in first few weeks". This is just patently untrue, as this study shows.

https://www.fda.gov/media/102332/download

To better understand the nature of the evidence obtained from many phase 2 trials and the contributions of phase 3 trials, we identified, based on publicly available information, 22 case studies of drugs, vaccines and medical devices since 1999 in which promising phase 2 clinical trial results were not confirmed in phase 3 clinical testing.* Phase 3 studies did not confirm phase 2 findings of effectiveness in 14 cases, safety in 1 case, and both safety and effectiveness in 7 cases. These unexpected results could occur even when the phase 2 study was relatively large and even when the phase 2 trials assessed clinical outcomes. In two cases, the phase 3 studies showed that the experimental product increased the frequency of the problem it was intended to prevent.

So the big one here, aside the from the safety issues and effectiveness issues in over half the vaccines, in slightly less than 10% of cases the vaccine actually made the problem WORSE.