Bringing up Thalidomide / Contergan in a discussion on current medicine is the best indication that you don‘t have the least idea on the topic. All rules and tests that eg the Biontech-Vaccine had to pass (and has passed) have been installed _after_ and _because_ of the Thalidomide catastrophy. Bringing up the topic of Thalidomide exactly disproves any point you are thinking you make, because the level of safety in medicine we have today has been raised to a level incomparable to what we had with Thalidomide.
What you are saying instead is: “Current medicine must be _very_ safe because todays‘ safety protocols are so much higher than what we had back then.“