Yes, MSG is horrible and hidden in many foods.
It is also in some vaccines. The nasal Flu Mist is especially high in MSG.
About 3 years ago my husband discovered that he had become allergic to MSG after we rushed him to emergency for what he thought was a heart attack. Turns out it was an MSG reaction to the MSG in the store-bought taco's and refried beans that I had decided to serve to the family and he had devoured.
We don't get vaccines, but I can only imagine how horrible a reaction that he would have if her were to unknowingly get the Flu Mist vaccine now. After the reaction that he had to just tacos and beans, I think that thought might kill him or at least hospitalize him. Yet nobody would make the connection since this isn't common knowledge. Sheesh...

Oh, by the way, he has improved his MSG reactions by of course avoiding it wherever he can, but also using Magnesium Oil (sprayed in his mouth). The magnesium subsides a reaction fairly quickly and prevents future ones, and drinking water with diatomaceous earth.