To counter the spread of the disease, Pakistan launched an eradication campaign in 1994. The country used to report 20,000 cases annually, according to government health officials. While the figure has come down significantly (five so far this year), the spread continues.

Pakistan administers more than 300 million doses of oral vaccine annually with the help of at least 350,000 vaccinators, according to the Pakistan Polio Eradication Programme.

Health workers, as well as accompanying security officials, are often harassed, ridiculed, taunted, threatened and targeted physically. At least 102 have been killed in the field, government officials say, including during campaigns carried out this year.

In addition to these attacks and refusals of vaccination, health workers also face other issues, including low pay, salary delays, and tough working conditions. Some told Al Jazeera they are paid as little as 1,360 rupees (approx $5) for an eight-hour day.

Some polio survivors working on the eradication campaign said they receive no transport or health benefits despite their condition, leaving them to walk through tough terrain and demanding weather conditions when carrying out their work.