> because they believed efforts to vaccinate against polio were in fact an attempt to poison Muslims

Or more likely a terrorist organization in those countries started such rumors to turn public sentiment against the west. Oh, and then the USG used a vaccination program to attempt to track down terrorists, which played a role in the take-down of Osama Bin Laden.

It's fair to say that there are compromised NGOs, based on the OBL incident alone.