sunspot.net - print edition: "They had heard a rumor circulating through the hot, dusty villages of northern Nigeria that the vaccine had been contaminated with an anti-fertility agent that would sterilize their children or perhaps infect them with the AIDS virus, all part of an American plot to depopulate the developing world. The villagers believed it.
It didn't matter that the World Health Organization, the Nigerian government and dozens of doctors and scientists dismissed the allegations as baseless, assuring the public that the vaccine taken by 1 billion children worldwide is safe.
'We just didn't like the vaccine,' says Umar."
This is what's called a 'credibility gap', or, in the common vernacular, a 'Bush gap'.