When I was a kid growing up (in the 50s & 60s), we were too worried about things like polio and nuclear strikes to worry about imaginary ailments.
Plus, every adult smoked everywhere and kids played in the dirt like they were meant to do.
I think that has something to do with it.
Hey, eat the right amount of the right kind of dirt and your immune system gets boosted rather well!
You are ignorant (unknowing, unaware, uninformed, insensible, unconversant, unfamiliar with, sophmoric).