Pakistan on Monday launched an anti-polio vaccination campaign as the total number of affected children rose to 104 in the current year, an official said.

"A five-day vaccination campaign across the country was launched on Dec. 16," said Zulfikar Babakel, a spokesperson for Pakistan's anti-polio program.

The campaign will target over 39 million children under the age of 5, with a major focus on the province of Khyber Pakhtunkhwa.

At least 75 new cases have been reported from the province this year. Babakhel said 260,000 polio workers will go door to door to administer the vaccine to children.

In April, a vaccination campaign ran into trouble when a fake video purporting to show school children falling ill after they were given the vaccine in the northwestern city of Peshawar went viral.

Some parents refuse to give permission to administer the vaccine, fearing it might make their children sterile or cause other complications.

Pakistan and Afghanistan are among only a handful of countries in the world where polio is still prevalent.

On Friday, Prime Minister Imran Khan urged parents to ensure their children are administered the anti-polio vaccine, saying it was a matter of "shame" that polio still exists in Pakistan.

The polio cases peaked at 306 in 2014, the year an offensive against the Taliban began, but there had been a sharp reduction since, with the number falling to just eight in 2017 and 12 the following year, according to official statistics.