Okay, I should probably have been a bit clearer about that. Polio eradication efforts everywhere in the world, including the US, were based around the oral poli

Okay, I should probably have been a bit clearer about that. Polio eradication efforts everywhere in the world, including the US, were based around the oral polio vaccine due to its apparent benefits in stopping vaccinated people from spreading polio. This was discontinued in the developed world, including the USA, a couple of decades ago (edit: and replaced with the inactivated polio vaccine - I though this was clear enough from the context...) after polio was eliminated there and the risk of spread from other countries was considered low enough. Entire age groups have never been vaccinated using the OPV. And of course it doesn't matter how well protected the population as a whole is if there's a subcommunity of people who regularly interact with each other who aren;t...