Health workers in a Pakistani tribal area on Monday announced a boycott of a polio vaccination drive to protest the killing of one of their colleagues last week. Abdul Ghani Marwat, who headed the government’s vaccination campaign in Bajaur near the Afghan border, was returning after meeting a local religious leader when his vehicle was hit by a bomb, killing him and injuring three others. The blast came amidst rumours the vaccination drive was a US plot to sterilise Muslim children. Some 1,500 health officials, including doctors, nurses and paramedical staff, on Monday wore black armbands and observed a “complete strike” in the region to protest against the killing, said a Health Department spokesman. “The strike will be observed till Wednesday to protest against the lack of security for health workers in the region,” the chairman of the doctors’ action committee, Daud Jan, told reporters. “The health workers have also decided to boycott the three-day polio vaccination drive beginning from Tuesday and they will take out a protest rally in Khar,” he said. Local health officials said that some 140,000 children could be affected by the action.