A campaign like the global polio eradication effort brings many challenges. Inevitably there will be external factors that complicate the effort even more. But if one of those factors is “religion”, things can get ugly.
And those often promote that the polio eradication effort is part of a larger strategic warfare plan, intending to sterilize Muslims or even worse. This causes local population to refuse vaccination for their children.
In Pakistan, anti-Western militants are blocking vaccination drives as long as the U.S. continues its drone attacks. And not long ago, in Pakistan, violent attacks against health workers took one life and injured two others.