Health workers have begun a campaign to vaccinate 9.5 million children against polio in 41 districts in Pakistan this week. This latest round of a national vaccination drive will include Islamabad and focus particularly on areas where polio-positive sewage samples have been found.

The anti-polio drive will be launched in 16 districts of Balochistan, 11 districts of Khyber Pakhtunkhwa, eight districts of Sindh, and five districts of Punjab, according to local media.

Despite major efforts to eradicate the disease in Pakistan, six cases of the highly infectious virus have already been reported this year. Further hampering the drive, vaccination teams and medical professionals have faced harassment and even physical attacks in some parts of Pakistan.

Pakistan’s PM Shehbaz Sharif, however, said the government “remains steadfast” in its aim to eradicate polio after a meeting with American billionaire philanthropist Bill Gates in Islamabad last week.

How serious a problem is polio in Pakistan?

Pakistan is one of only two countries in the world where polio is still endemic, the other being neighbouring Afghanistan, according to the World Health Organization (WHO).

The highly contagious viral disease largely affects children under the age of five. Children infected by poliovirus can suffer paralysis and in some cases death.

The South Asian nation launched a vaccination programme as part of its Polio Eradication Programme in 1994. Officials say the country used to report more than 20,000 cases annually.

Despite administering more than 300 million doses of the oral vaccine annually and spending billions of dollars, the disease is still rife across Pakistan.

This year, four vaccination campaigns targeting more than 43 million children have already been undertaken as authorities claim they are in the “last mile” of their fight against polio in the country of 235 million people.

How many cases have been reported in Pakistan?

Since 2015, Pakistan has reported 357 polio cases, including six this year. One of the victims, a two-year-old boy, died in May.

Officials said all of this year’s cases belong to the YB3A cluster, which they said originated in Afghanistan, where four cases have been reported this year.

In addition to human cases, wild poliovirus type 1 (WPV1) has frequently been detected in environmental samples taken across the country. This year, WPV1 has been found in 45 of Pakistan’s 166 districts.

How does Pakistan run its polio immunisation campaigns?

Nationwide immunisation campaigns involving more than 350,000 health workers are run in phases with vaccine desks set up at health centres and health workers going door to door. The campaigns are organised by the government-run National Emergencies Operation Center (NEOC), which has been tasked with running Pakistan’s Polio Eradication Programme.

Field workers go door to door over the course of a specified number of days, vaccinating children under the age of five.

Vaccines are also administered at land and air borders, including to adults, and on motorways connecting major cities across the country.

What are the issues facing the polio campaign?

Resistance to the polio immunisation drive grew in Pakistan after the CIA, a United States spy agency, organised a fake hepatitis vaccination drive to track al-Qaeda leader Osama bin Laden, who was killed in 2011 in Pakistan by US special forces.

Misinformation linked to religious beliefs has also been spread, claiming that the vaccine contains traces of pork and alcohol, which are forbidden in Islam.

Disinformation, agenda-driven campaigns, myths, community boycotts and mistrust in the government have also been factors behind refusals. But officials said government campaigns are helping change bad perceptions.

Health authorities in Pakistan have listed seven districts where polio is “endemic”. All seven are in the northwest, in Khyber-Pakhtunkhwa province. Officials said the security situation has been the biggest obstacle in reaching the target population in the province bordering Afghanistan.

In addition to the security situation, health officials say a target population that moves from one place to another, which may be carrying the YB3A variant, has proven to be a challenge.

Why have health workers and security officials been targeted?

Health workers and security officials accompanying them have been harassed, ridiculed, taunted, threatened and even targeted physically.

At least 102 polio field workers, officials and security personnel have been killed, including at least six in campaigns carried out this year.

In recent years, the Pakistan Taliban has killed dozens of health workers and members of the security forces involved in polio campaigns. But officials believe the reason for the violence is not the polio programme alone.

“Over the last few years, it is not the polio programme that is targeted, but unfortunately, the targets are the security personnel guarding the teams because, given the security situation in some parts of the country, they become soft targets when they are in the community,” Dr Hamid Jafari, the WHO’s director of polio eradication, told Al Jazeera.

What other issues affect the health workers?

Low pay, salary delays, lack of assistance and compassion, and tough working conditions are some of the other issues facing the field workers.

Some health workers told Al Jazeera they get paid as little as 1,360 rupees per day (about $5) for at least eight hours of work. Catch-up days when they go out in the field after the end of the campaign to vaccinate children who were missed are not paid, they said.

In addition, some polio survivors now working on the campaign do not receive help with transport or health benefits despite their conditions, leaving them to walk in poor weather and tough terrain to carry out their work.

Some staff lamented the lack of pay parity, saying people working with international organisations involved in the campaign are paid much more.

What is the outlook for the polio eradication campaign?

Dr Shahzad Baig, who was the NEOC chief until May, told Al Jazeera that the aim was to make Pakistan polio-free by 2026.

“That is our target at the moment,” he said before he was replaced.

However, after a Technical Advisory Group meeting organised by the WHO that took place in Qatar in May, there are increasing concerns over the “deteriorating situation of the disease” in the country, according to a report by Pakistan’s Dawn newspaper.

A Pakistani official quoted in the report said that at the meeting, “We faced an embarrassing situation as all the gains made by Pakistan in 2021 have been lost and the virus has re-emerged in three blocks.”

Health officials, however, remain hopeful, given that the number of positive cases has decreased significantly over the past five years – from 147 in 2019 to six so far this year.

“The programmes in Pakistan and Afghanistan are very mature and have learned a lot,” Jafari said.

“Despite changes in government and security situations, these programmes have evolved, adapted and adjusted. And that’s why they have a level of population immunity that you’re not seeing outbreaks of paralytic polio cases.

“It’s not a widespread problem across Pakistan. It’s not even a widespread geographic problem. It is now a matter of getting to these final, hard-to-reach populations. When you start reaching these populations, progress happens very fast.”