There will be a post-approval Phase IV surveillance stage to check for rare or long-term adverse effects.

> I recall a famous drug that was given in the 70s and it produced birth malformations.

You’re probably referring to thalidomide.

> What if someone has for XYZ reason more reverse transcriptase than usual? Will his-her DNA be altered?

Highly unlikely since the vaccines don’t code for transposable elements that could integrate into the host genome.