If not, wonder how many vaccines they change just a little bit and don't have to go thru testing? Thinking about moderna wanting to just add the covid vax to existing flu vaccines. I'm going to pass on flu vax this year as we would never know the true formulations of these supposed vaccines if they are allowed to just change them on the fly.
From experience you cannot change your formulation once clinical trials have been started. If any substantial changes are made (not talking about labeling, secondary packaging and the like, though these do need to be qualified) then you have a new product.
This means even changing the ratio of one metal to another, say in an alloy. You must start over with all the animal testing. After successful completion of animal testing the exact formula can be used in clinical trials.
The question is was this formula first:
1. Thoroughly chemically characterized?
2. Tested to all the recognized consensus standards according to FDA and foreign notified body guidelines?
3. Passed all the required tests?
If not, why? And if so, how did they get a pass from the FDA?