Because of the shootings, Sindh province Health Minister Sagheer Ahmed ordered the World Health Organization's anti-polio drive in Karachi stopped, the Pakistani News Agency reported.
In Karachi, the attacks occurred in three areas of the sprawling port city on the second day of a nationwide three-day drive against the disease that is endemic in Pakistan.
In Peshawar, a woman who was shot along with another female worker died of her injuries in a hospital, the Pakistani News Agency said.
Police said a gunman also killed a volunteer for the World Health Organization's anti-polio campaign in Gadap Monday.
Campus cop fatally shoots Texas student during traffic stop
Exploding whale video goes viral on Internet