As a school kid in the 50s we all had friends and classmates variously hobbled by polio. It was definitely the health scourge of our day, then along came a polio vaccine and now hardly anyone ever thinks about polio any more. Some few also died of the disease. So the Phactor is wondering when and where the next outbreak will be in the USA? Polio is not gone from the Earth, and all it will take is one non-vaccinated person, the unfortunate offspring of irrational parents, to travel abroad and bring the disease back, and then an outbreak will occur among all those non-vaccinated kids, who were up until then protected by the vast majority who got vaccinated. This is happening right now with measles, a not completely inconsequential childhood disease. In the "old" days if you did not have an up to date vaccination record, you could not attend public school. Now 2% of all kids in California are not being vaccinated. So when the inevitable happens, everyone should just say you could have, you should have, but you didn't. It's all on you. Tough. Clearly it's in the best interest of the country for the USA to restrict overseas travel of non-vaccinated people, and they should be the ones clamoring most loudly for the restriction. Now of course some small chance of vectoring a disease can also come from visiting persons, so anti-vaccers should realize the potential risk and their only protection is too become extremely xenophobic, stay at home, don't travel, don't send you kids to school, and don't socialize, or face the consequences of your actions.