Three vaccinations used to be enough. We received our other immunizations by going outside, digging in the dirt (literally), and interacting socially- meaning "face to face".
Children today stay indoors, play video games, interact socially via media, have shitty diets, and get no exercise.
Did I ever get sick? Damn right I did. The flu, ear infections, chicken pox, mono (Infectious Mononucleosis).
I even broke my leg playing outdoors. I once fell out of a tree and to this day sport a prominent knot on my forehead. I was lucky to have survived.
I remember thinking of my ills as the process of healing. And I did.Heal.