@Bordois
It would have been an interesting experiment to not let people know what brand they are actually getting to see what symptoms get reported (obviously there round be a code in the batch reference so those that need to know could use the information). Probably some ethics concerns with that, although I dont recall ever being told what brand of vaccine I'm getting previously
The "nocebo" effect is well documented. If you think something is going to do you harm, the mind "invents" the issues you are afraid of. It's really interesting, because the effects/symptoms are "real", but not because of what you have just been given, which may well be nothing more noxious than water.