Why does it take 20 years? Except, of course, that it does not work nowhere near as well as it is being promoted - aka hyped.
replymRNA vaccines are also quite different. Do they modify the DNA? Of course not. So that's already very different.
Let's see... first of all, 14 years ago with the discovery of the base mechanism, not of specific treatments. So specific treatments need to be developed, delivery systems need to be developed, side effects reduced. Then you need safety tests and efficacy tests.
reply> mRNA vaccines are also quite different. Do they modify the DNA? Of course not. So that's already very different.
And yet it took more than 30 years after the first mRNA experiments to develop a successful vaccine. Why it should be so much faster for CRISPR & Co?