The deceased also includes a police constable, DPO Ejaz Khan had told The Express Tribune.
The second woman polio worker who was injured succumbed to her injuries later.
"The two-member team was administering polio drops in an Afghan refugee camp and its surrounding areas when two gunmen opened fire on them, killing one lady worker and a policeman and wounding another lady worker and a passer-by," Muhammad Ejaz Khan said.
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The injured were moved to King Abdullah Teaching Hospital where one lady health worker and a male constable were pronounced dead, while the other lady health worker was being treated.
Related: Crippling virus- number of polio cases reaches 18
Following the attack, the area has been sealed off by police commandos.
No one has claimed responsibility for the attack as yet.
Last year the number of polio cases recorded in Pakistan soared to 306, the highest in 14 years.
Pakistan is one of only three countries where polio remains endemic. Attempts to eradicate it have been badly hit by militant attacks on immunisation teams that have claimed 77 lives since December 2012.
The militants claim the polio vaccination drive is a front for espionage or a conspiracy to sterilise Muslims.
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