That is interesting except it does not take into account that if ya eats fruit and vegetables already you don;t really need to take all that stuff..
Its because of most people poor food choices and snacks they they need to take supplements.
I am not immune to that either. Some days I make much better choices for food and snacks than others... Eat some fruit everyday.. Have some veggies. I would only supplemet mostly with th Zinc, Magnesesium, EXTRA vitamin D
and a multivitamin that has all these things in it already.. One should have a pretty good immune system with that.
I have had FLU twice in my lifetime as an adult.. I was over it within a few days.. I do not get annual or semi annual flu shots and never have. Same for my wife.
Wash yer hands when ya come in and do it often and you will stay fairly healthy.
Just my experience. Yours may vary..