I'm old enough to remember both of the polio mass vaccination events, though I was too young to be aware of how the government informed the public about availability, clinics, and such. What I do remember was going to the local middle school in the late afternoon or early evening and standing in a long, long, densely packed queue that extended for 2 or more long city blocks outside the big lunchroom on the school's first floor. Inside, there were tables set up with a couple of people in white coats administering the vaccines.
The first polio vaccine was a shot and the line took forever. The repeat vaccine (a couple of years later) was by eating a sugar cube, so the process was a whole lot quicker.
