[Jiggly]

Oh God, they couldn't vaccinate firstly young people. Not make experiments on those adults

Forgive me, but I think you've got this confused. They already conducted multiple human trials, and passed those trials with flying colours, before they were approved as SAFE for everyone. They aren't experimenting on old people. They already know they are safe, and they already know the vaccines work. There are other vaccinations that are still in humans trials/the experimental stage, though