--ditto--one of my boyhood acquainences died of polio in 1950---the present generation doesn't apparently know of or appreciate the relief polio vaccine, for example, gave to parents---
It is about the age the kids get the vaccine. AND the total vaccine load that caused the epidemic of autoimmune diseases.
The schedules of the 50s and even 60s have the risk reward profile that you remember. This profile has changed due to the massive schedule that is imposed.