The most consequential moments of our lives are often the ones we barely notice. A child standing in line at a small town library doesn’t know he’s part of a public health victory. He only knows someone handed him a sugar cube. In 1962 (ish), my mother took me to the Carnegie Library in Plainville, Kansas to receive the new oral polio vaccine. I remember a nurse squeezing the dope into a sugar cube with an eyedropper. I don’t remember anyone protesting outside, demanding medical freedom, or...