The United Nations in Pakistan has pulled all staff involved in the campaign off the streets, spokesman Michael Coleman said.
The government said immunization was continuing in some areas without UN support although many workers refused to go out. Women health workers held protests in the southern city of Karachi and in the capital, Islamabad.
“We go out and risk our lives to save other people's children from being permanently handicapped, for what? So that our own children become orphans?” health worker Ambreen Bibi said at the Islamabad protest.
The government was caught off guard by the violence, saying they had not expected attacks in areas far from Taliban strongholds and they would have to change tactics in the health campaign.
“We didn't expect such attacks in Karachi,” said Mustafa Nawaz Khokhar, minister for human rights, who oversees the polio campaign. He was referring to the southern commercial hub where there have been attacks this week.
“In far flung areas where the threats are more pronounced, we have been providing polio teams security.”