For vaccine manufacturers, it's all the same people. Even if you have whistleblowers come forward, they're ignored.

Here's one quick way to rig any clinical trial: Anyone and everyone that has any kind of negative reaction or health condition gets disenrolled. Since it's 'double blind' it appears on the surface level that there's no way to know who's in what group. Naturally, the end result is always the same: The test group had the same number of reactions as the control by the end of the study.