Yellow fever is spread through mosquito bites and polio is spread person-to-person. An imported case of yellow fever is nearly impossible to spread, while an imported case of polio is virtually certain to spread.
Sorry, but it's simply naive to think that in today's global world we would not import polio. It's already happening right now in the US. The only thing stopping the spread is our current high vaccination rate. You'd have to cut travel to zero in both directions to stop it.
Yellow fever is spread through mosquito bites and polio is spread person-to-person. An imported case of yellow fever is nearly impossible to spread, while an imported case of polio is virtually certain to spread.
Sorry, but it's simply naive to think that in today's global world we would not import polio. It's already happening right now in the US. The only thing stopping the spread is our current high vaccination rate. You'd have to cut travel to zero in both directions to stop it.