Gunmen in Pakistan have killed six people and wounded several others who were working on an anti-polio vaccination program, amid accusations that the campaign is part of a Western conspiracy against Muslims. The five health workers were shot in three separate attacks on Monday and Tuesday, presumably by Taliban fighters who have previously denounced their efforts to immunize millions of children across the region.

In response, the United Nations and the Pakistani government have suspended the eradication program in Peshawar province and in Pakistan's second-largest city, Karachi. More than 24,000 polio workers were participating in the three-day long campaign to deliver the vaccinations.

The latest incidents underscore the dangers of using NGOs as a cover for intelligence operations. In 2011, the CIA set up a fake vaccination program in Abottabad, in the hopes of obtaining DNA samples from members of Osama bin Laden's family, who were in hiding there. After bin Laden was killed in an American commando raid, the Pakistani doctor who helped to orchestrate the ruse was given 33 years in prison, and has allegedly been tortured for cooperating with a foreign government.

While the plan was part of a successful intelligence operation, it only fed distrust of Western organizations among regular citizens and fueled rumors about more nefarious plots involving the U.N. and other relief organisations, like the belief that vaccinations are made from pig products (which are forbidden by Islam) or are part of a scheme to sterilize Muslims. Not only do the rumors undermine the program's effectiveness, they obviously put real health care workers in danger. 

Despite being nearly eradicated throughout most of the word, four nations—Afghanistan, India, Nigeria, and Pakistan—have seen a major resurgence in the disease, in part because of resistance to vaccination programs. There have been at least 200 cases of children in Pakistan being paralyzed by polio in 2011, the worst outbreak in 15 years.

Correction: India used to be one of four nations officially declared "polio endemic," but was removed from the list in 2011.