The women were vaccinating children in Kaga Wala, a village perched on the edge of the country's volatile tribal belt, when two men opened fire, said Shafeeullah Khan, a local police official. One of the workers was critically injured in the attack and was being treated for gunshot wounds at a Peshawar hospital.
No one claimed responsibility for the assault, but last year the Pakistani Taliban denounced polio vaccination drives as a guise for U.S. spying activity. At least a dozen polio workers have been killed in Pakistan since mid-December.
Government officials have been assigning police to accompany polio vaccination teams. However, the attacks have continued, and several police deployed with vaccination crews have been killed and injured in militant assaults. Khan said the two workers attacked in Kaga Wala had been offered a police escort, but they declined.
Pakistan is one of three countries where polio remains endemic. Vaccination workers from the other two nations, Nigeria and Afghanistan, have also been killed in recent months. Despite the violence, Pakistan has continued its vaccination efforts, and last year the number of polio cases dropped to 56 from 173 in 2011.