Fun fact: Alcohol is poison :) Garlic is a neurotoxin (and probably many others I am too lazy to remember).
There was once an outcry for having Glyphosat in beer. Like 'oh no, there is a potential poison in our poison, what should we do?'
Like @irime already told you, adding a booster triggers an immune response. Probably similar to many natural remedies that 'strengthen the immune system' or like eating a bit of dirt.
As to the immunity of that industry, do you have any facts? Like actual harm done?
Facts to their immunity? Yes I do. Here you go -
https://www.law.cornell.edu/uscode/text/42/300aa-22
Actual harm done? Come on. You have brain just like me. There wouldn’t be a Vaccine Injury Trust Fund if there weren’t injuries! That’s an actual government agency for, wait for it, vaccine injuries. So yes there wouldn’t be this agency if there wasn’t actual harm being done. And there’s no science to refute there, the agency really does exist.