By that same logic why wait for any studies on the vaccine at all? Why not just start administering it as soon as it's developed (en masse)?
The rigor is to give the public confidence that we're better off getting the vaccine than not.
The rigor is to give the public confidence that we're better off getting the vaccine than not.
The first two phases are the safety tests, the third one is efficacy (so we knew the vaccine was "safe" after phase 2, we just didn't know the efficacy - that's what the poster above is alluding to).