You would be immensely surprised as to the varying reasons and literature and science brought to bear as to why this statement is incorrect.
Longitudinal cross sectional studies, for one, comes to mind.
Never before used technology to innoculate the ENTIRE population at once, never having been used before also comes to mind.
That only scratches the surface for people objecting to being forced, does not get into nitty gritty details.
Those alone should be sufficient to not inject the entire human population on planet earth with an experimental unapproved medical treatment.