“Vaccine scares that lead portions of the population to forgo vaccination could become more common as more diseases become eradicated.”
This is becoming a major problem for developed countries – that is to say, high GDP countries where people mostly have jobs and houses and electricity, and TV – and of course, that bringer of disinformation about vaccines, the internet.
Seriously: there are some 300 000 ANTI-vaccine sites out there, according to contacts in the USA, and some of them are so rabid they would make neo-nazis look respectable.
As I have written elsewhere – in a comment on an article in The Scientist – it would be ironic if developing countries started instituting stricter vaccination controls for travellers from the more affluent world. It is coming, though: the first importations of diseases like measles from Europe to the Americas have already occurred, and I am sure the incidence of these reports will rise as vaccine paranoia grows.