ISLAMABAD (AP) — Pakistan on Sunday launched its first anti-polio campaign of the year, targeting 44.2 million children under the age of five.

Pakistan and Afghanistan are the only two countries in the world where polio continues to threaten the health and well-being of children. Polio affects the nervous system of children and ultimately leads to paralysis.

Prime Minister Shahbaz Sharif kicked off the nationwide drive by administering polio drops to children in the capital, Islamabad, saying Pakistan was unfortunately among the few countries that still suffered from the disease.

Twenty cases were reported in the tribal North Waziristan area last year, though the disease was contained among other children through immunization, Sharif said.

Around 44 million children in 156 districts will be immunized.

This includes 22.54 million children in Punjab, 10.1 million in Sindh and 7.4 million in Khyber Pakhtunkhwa provinces.

Sharif said his government along with other stakeholders, including U.S. billionaire Bill Gates and the World Health Organization, were effectively contributing to polio eradication in Pakistan.

He gave away appreciation certificates at the launch to frontline polio workers and praised their “invaluable sacrifices”.

Pakistan has witnessed frequent attacks on polio teams and policemen deployed to protect them. Militants falsely claim that vaccination campaigns are a Western conspiracy to sterilize children.