Since July 2012, 31 people have been killed in Taliban-led attacks on anti-polio campaigners in Pakistan.

Most recently, two policemen providing security to polio vaccinators in Swabi were killed when gunmen on a motorbike attacked them. In a separate incident, unidentified gunmen opened fire on polio workers in Peshawar, killing one.

One and a half million children are at risk of polio in Pakistan, which along with Afghanistan and Nigeria are the only three countries in the world where the virus - which spreads from person to person - remains endemic.

Gulnaz Nighat, the health official in charge of the anti-polio campaign in Karachi's Gulshan-e-Buner district, vividly remembers the day her sister-in-law, Fehmida; and niece, Madiha - both health volunteers - were killed.

On the morning of December 18, 2012, two men on a motorbike exchanged a quick "salaam aleikum" with the imam of a mosque in the area. Having brought their four-year-old cousin to get vaccinated, they asked for the polio workers. The imam pointed towards Fehmida and Madiha, who were administering oral polio vaccines to children at a house nearby before disappearing into the mosque. Ten minutes later, two shots were fired. The imam ran out to see Madiha fall to the ground as Fehmida ran inside the house. The two men chased her inside and gunned her down as well before escaping on their bike.

Gulnaz heard the shots but didn't make anything of it because she lived in an area where violence is rampant. A few minutes later, she heard police and ambulance sirens. "That is when I got worried. I called my niece's cell phone five times but there was no answer." Donning her abaya, she raced to the scene. "The moment I saw Fehmida and Madiha's bodies, I wanted to scream but not a sound would escape me. I kept arguing that they must have fallen asleep. I couldn't grasp the reality of what had just happened."

Many expected Gulnaz to abandon the programme out of fear, but instead the killing of her relatives only emboldened her.

When asked whether she feels afraid, Gulnaz told Al Jazeera, "Allah has given me strength. We are doing this for the future of this country. We need to move towards light, not disappear into darkness." After pausing for a moment, she softly stated, "Whenever I go in the field, I feel that my niece and sister-in-law are walking right beside me. It makes me stronger to know that they didn't die in vain. It is my duty to finish what we started together."

Security threats

In 1994, Prime Minister Benazir Bhutto launched the Lady Health Workers Programme under the auspices of the Ministry of Health in an effort to introduce essential health care facilities to vulnerable communities. Today, Pakistan has approximately 110,000 Lady Health Workers in the field.

There have been numerous killings and the girls are very scared. Volunteers have dropped out of the campaign and even the policemen are afraid. - Ayesha Bibi, a health supervisor in Peshawar

Despite running one of the largest community health-care programmes in the world, Pakistan's polio eradication efforts are troubled. Dr Elias Durry, the head of the World Health Organisation's Global Polio Eradication Initiative, told Al Jazeera that "security concerns and negotiated access are the two major problems facing polio elimination. The good news is that there have been no cases from [Pakistan's western province of] Baluchistan, and the polio epidemic is now confined to certain pockets. The bad news is the polio ban in certain areas, the killing of the workers and the lack of access that leads to missed children."

This year, Pakistan has reported 75 cases of polio, with 52 cases occuring in its federally administered tribal areas. With security concerns high, polio vaccination teams lack access to the North and South Waziristan regons, meaning that close to 290,000 children have been prevented from receiving vaccinations. Nationwide, 90 percent of polio cases occur among ethnic Pashto families, many of whom live in Pakistan's northwest.

Ayesha Bibi, a Lady Health Supervisor in the northwestern city of Peshawar, argues that the level of security provided by the government is severely inadequate in the country's high-risk areas. "There have been numerous killings and the girls are very scared. Volunteers have dropped out of the campaign and even the policemen are afraid," she said. Ayesha told stories of changing cars and license plates to avoid Taliban monitoring but claims that she continues to receive death threats.

"This issue is very politicised," said Saira Tarrar, minister of state for national health services, regulation and coordination. "We need two policemen per team, and that would mean about 3,600 policemen. Given our security constraints, that is impossible. I also monitor the prime minister's Polio Cell. We can only provide technical support and advise on security but cannot implement it. It is not our job."

Refusing the vaccine

According to information obtained from the WHO, Pakistan's National Immunisation Day in November aimed to vaccinate 34 million children. But some polio workers boycotted the initiative. They earn just $2.50 a day, yet many have not been paid for the past six months. On top of that, they face tremendous risks in their day-to-day work.

As a result of the boycott and the security risks, the National Immunisation Day was delayed in 70 districts across the country. Official statistics released by the WHO show that 2.34 million children were missed during this campaign - of whom 47,099 children were not immunised because their families refused the vaccine.

Apart from the inaccessibility of certain areas and the presence of polio "reservoirs" like Karachi, "security concerns and army operations also lead to a great movement of people. If we don't vaccinate children, they can quickly become the main carriers of the disease," said Durry.

Some Pakistanis refuse to have their children vaccinated because they believe that it is "un-Islamic" or could be an American ploy to sterilise children. After news emerged that the US' Central Intelligence Agency employed a doctor to run a fake hepatitis B vaccination programme in an effort to find Osama bin Laden, conspiracy theories about health workers' activities have abounded - such as claims that vaccinators mark houses to be targeted by US drones. Polio workers have been accused of being CIA operatives, and the campaign has suffered incalculable damage.

However, according to Nasir Nawaz, a district health communication support officer in Sindh province, vaccines are most often refused by Pakistanis living in very poor areas, where basic needs for water, food and electricity are unmet. In such circumstances, polio workers who bring vaccines instead of food and clothing are promptly, and aggressively, turned away.

Durry told Al Jazeera, "The real heroes of this campaign are the vaccinators who keep doing their jobs in high-risk areas without fear. They are not soldiers who are trained to battle. They are just there to do the right thing. If there is anyone who deserves to receive the Nobel Prize, it is the health workers."

Health workers like Ayesha refuse to leave the campaign despite the threats and the lack of pay. "We play with our lives every day, but we do this for our country. What will happen to our children if we stop? We can't give into Taliban threats." Pausing for a moment, she says proudly: "I am a woman from FATA [Pakistan's federally administered tribal areas]. I am not one of those scared ones."