A federal government campaign to vaccinate more than 40 million children under five against polio in Pakistan has been suspended following a series of attacks on workers and police over the past week.

On 23 April a police officer responsible for protecting polio workers was gunned down in Bannu. The same day, a polio worker was injured with a knife in Lahore by a man refusing to allow his child to be vaccinated, citing a recent hoax video that claimed children were becoming ill after the immunisations.

A second police officer was killed in Buner as he accompanied a polio team.

A 35-year-old female polio worker was shot and killed on Thursday in Chaman, Balochistan, close to the border with Afghanistan. A 24-year-old colleague was also seriously wounded in the attack.

Further attacks on staff in Sindh, Balochistan and Punjab have also been reported.

The violence was preceded by a series of rumours intended to derail Pakistan’s campaign to eradicate the disease.

On 22 April several thousand children were taken to hospital in the north-west of the country by panicked parents after a video circulated on Facebook in which a man attested that children were falling sick following vaccinations.

Facebook Twitter Pinterest A damaged health centre on the outskirts of Peshawar, set alight by a mob following rumours of children suffering bad reactions to polio vaccinations. Photograph: Abdul Majeed/AFP/Getty

Hours later, a bizarre second video emerged, in which the same man attempted to show that children had fallen ill after the immunisations by ordering school boys to lie down in hospital beds and pretend to be unconscious. A mob went on to set fire to part of a government health facility. Thirteen people are being investigated over the incident.

The disruption has led to the suspension of the campaign’s “follow-up and evaluation”, earmarking children missed in the initial intensive vaccine drive.

Vaccinators and police teams have previously been targeted in the country, where rumours have persisted about immunisation programmes being harmful or a cover for foreign interests. But a shift to recruiting local workers for the door-to-door campaigns – people known and trusted in their communities and with the right language skills and access – had led to better acceptance.

Pakistan has seen a 96% reduction in polio cases since 2014. It is one of three countries that has yet to eliminate the disease, along with Afghanistan and Nigeria.

Khalida Nasareen, 61, area supervisor in Orangi Town in the north of Karachi, said: “Absolutely, God willing, we will end polio soon, but unfortunately bad people try to run down our work. We have to face that propaganda head on. It hurts but it passes and we will bring it back to where we were.

“If we can save the life of one child, I feel as though I’m contributing to saving humanity. Ours is a poor neighbourhood which lacks basic services and with poverty comes lack of awareness and education. It’s a cause I’m willing to die for.”

Facebook Twitter Pinterest Right, Khalida Nasareen, 61, area supervisor in Orangi Town, in the north of Karachi. Photograph: Khaula Jamil/Courtesy of Bill & Melinda Gates Foundation

About 260,000 frontline workers are involved in the vaccine campaign, supported by well-known personalities from the worlds of religion, sport, acting and medicine.

Some parents still complain about the frequency of vaccination drives in high-risk areas, or the lack of access to basic healthcare and filtered water in underserved communities. But the National Polio Emergency Operation Centre, a joint effort from the government, WHO and Unicef, has recorded a drop in vaccine refusals, and confirmed polio cases are down from approximately 20,000 every year in the early 1990s to 20 or fewer a year since 2016.

“Vaccinating all children in every campaign is important to attain full immunity against the polio virus,” said the prime minister’s focal representative on polio, Babar Bin Atta. “Fortunately, children who are vaccinated against polio multiple times are able to fight the virus. The more doses of the polio vaccine a child receives, the higher the chances of escaping lifelong paralysis.”

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Aside from misinformation scares, tackling polio has proved challenging due to the large population, as well as the amount of movement within the country and to and from Afghanistan.

In tandem with the door-to-door campaign, teams are deployed at train stations, bus stops and on key junctions at the entrance and exit of cities to reach children in transit.

Last month, an all-age polio vaccination was introduced for travellers crossing the border between Pakistan and Afghanistan.

On Thursday, two new cases of polio in Bannu and North Waziristan, in the north-west of Pakistan have been confirmed by the National Emergency Operations Centre in Islamabad. This brings the total number of polio cases in the country to eight in the first four months of 2019. A total of 12 cases were recorded across the country in 2018.

Environmental surveillance earlier this year detected poliovirus in the sewage of 10 cities in the country.

In 2015 the government had to prove that the vaccine used was not ‘Haram’. A laboratory under the Drug Regulatory Authority of Pakistan tested the vaccine and certified it as Halal. This was in response to a persistent rumour that the oral vaccine had hormones added to it to make children sterile.