Back in the 1960s, the United States was still requiring children to be immunized against smallpox. You probably have not heard of smallpox since it is the only viral disease eradicated by vaccination. There has not been a documented case from community transmission since 1979. It took a Herculean effort to eradicate smallpox, with almost all the countries in the world — even bitter ideological, political and military enemies like the United States and the Soviet Union — coming together in that endeavor. Everyone agreed that it was a threat to humanity, regardless of political affiliation or political boundaries.
In 1969, a debate took place between John M. Neff, MD, and Samuel Lawrence Katz, MD, on whether to continue to immunize children against smallpox given that, at the time, the disease was under control in the country. (Think of polio today, where it is found only in areas of Central Asia, yet children in the United States and other countries continue to receive the vaccine.) The debate was televised and archived by the US National Library of Medicine. It is about 28 minutes long: