A Pakistani polio worker administers the oral polio vaccine to an infant in a Christian colony in the slums of Islamabad on Wednesday, Dec. 19, 2012. (AP Photo/B.K. Bangash)

Photo by: B.K. Bangash

A Pakistani polio worker administers the oral polio vaccine to an infant in a Christian colony in the slums of Islamabad on Wednesday, Dec. 19, 2012. (AP Photo/B.K. Bangash)