Pakistan remains polio free—despite covid-19, the Afghan conflict, and a waning global eradication effort

Polio and the war on terror

Jan says the US led “war on terror” that followed the 9/11 attacks had a big effect on polio eradication programmes in Khyber Pakhtunkhwa and erstwhile FATA, areas believed to harbour militants. “In 2011, the eradication drive suffered a big blow after a physician, Shakil Afridi​, allegedly appointed by the CIA, was arrested​ for carrying out a fake hepatitis screening campaign to track al-Qaeda’s former chief Osama bin Laden,” Jan says.

In 2012, the Tehreek-i-Taliban, the militant group which openly operates in Khyber Pakhtunkhwa, banned anti-polio campaigns in erstwhile FATA’s North​ and South Waziristan.​ “A section of people in the province, influenced by religious hardliners, also suspected polio vaccinators to be agents of the west who are trying to control the Muslim population,” Basit says. There have been militant attacks on polio workers and the police accompanying them. Since 2012, militants have targeted more than 70 polio workers.2

Jan notes that in 2014, after the Pakistani army launched a successful anti-terrorist operation in erstwhile FATA, the polio eradication drive found its feet again. In 2015, the work at the localised emergency operations centres intensified, pooling all human resources under one platform. “Plus, improved monitoring, an integrated approach, quality campaigns, increasing the age group for inactivated polio vaccine to five years (from the previous bracket of six months to two years), revamping the communication strategy, and improving wages of field workers to $6 a day led to the decline in the number of cases,” Jan told The BMJ.

Keeping up the effort

Yet, sustaining the momentum of the campaign has been challenging for Pakistan. In 2017, when it recorded only eight wild poliovirus cases, there were expectations that it would be able to eradicate polio soon. But the cases surged to 12 in 2018 and then to 147 in 2019. Jan points to internal conflicts within eradication teams, a leadership vacuum, and low wages ($3 a day for field workers) as the reasons behind the rise. In some cases, unvaccinated children were marked vaccinated by polio workers under pressure from their parents. A polio eradication programme official anonymously told The BMJ that many people who live below the poverty line in the belt starting from Kohat to South Waziristan in Khyber Pakhtunkhwa demand clean drinking water and better sanitation facilities first before allowing their children to be inoculated.

In Karachi, Sindh’s densely populated capital, Farhat Parveen, the executive director of the National Organisation for Working Communities, a non-profit organisation that looks after the rights of women polio workers, says that many people have been indoctrinated by “Taliban influenced Islamists.” Parveen says these people refuse oral polio vaccines for their children.

Adnan Khan, an Islamabad based independent researcher on infectious disease and public health, told The BMJ that some women living in the country’s urban slums may turn away polio teams if male family members are not at home. “There are also households who consider polio workers as outsiders if they hail from a different tribe, caste, or speak a different language,” he says.

In 2015, Pakistan arrested over 500 parents for refusing to allow their children to be inoculated.3 Four years later, locals in Peshawar, considered the world’s largest polio reservoir, set a hospital on fire after 700 children reportedly fell sick after vaccination.4

Basit says that government agencies have been blocking anti-polio vaccine propaganda on social media while influential religious leaders have been roped into the programme to dispel myths about vaccines.

Stressing that high risk districts are routinely monitored while the security of field workers and their access to newborns, new migrants, and new settlements has improved, Basit adds that the 1% of the children who are not covered under the programme are likely to develop “herd immunity.” Although the pandemic stalled the polio vaccination programme for a few months, it has picked up again.

Poliovirus in environmental samples

What worries experts now is the prevalence of poliovirus in sewage. Last year, eight cases of circulating vaccine derived polioviruses (cVDPV2) were reported in Pakistan.

Khan says, “Because of the recent turmoil in Afghanistan, vaccination campaigns have not been regular, but surveillance confirmed the presence of wild poliovirus and cVDPV2 in environmental samples, suggesting that the vaccine is reaching these areas This is likely to be because of vaccination in the bordering areas of Afghanistan.”

But if cVDPV2 is spread from one unvaccinated child to another in communities with low immunisation rates, it can mutate and take on a form that can cause paralysis. Both Pakistan and Afghanistan, which are considered as one epidemiological block by WHO, now report more cases of paralysis from vaccine derived polio than from the wild poliovirus.

Faisal Sultan, special assistant on health to the prime minister, told The BMJ, “The challenge is to ensure that these environment samples go down to zero by diligent follow-up campaigns and ensuring that no child is left behind. This is especially hard in mobile populations that include seasonal workers.”

So far this year, there have been no cVDPV2 cases reported in environmental samples in Pakistan.

Pakistan’s poliovirus transmitted to Africa

Meanwhile, Malawi reported a wild polio outbreak in February after being declared free of all forms of wild polio in 2020, and the strain has been linked to one from Pakistan.5

Sultan says the Malawi case is genetically linked to a version that circulated in southern parts of Pakistan until 2019 but disappeared after that.

Pakistan’s surveillance for acute flaccid paralysis and environmental samples are the strongest that any country has, he says, and the chance of missing any cases, therefore, are “very remote.” He suspects it came from somewhere in the world where there are “pockets of immunity gaps and non-existent environmental surveillance.”

Zainul Abedin Khan, of WHO’s polio team in Pakistan, says that global polio epidemiology shows that the poliovirus always finds susceptible populations in remote or access compromised areas where health and immunisation services are inadequate, or among high risk and mobile populations that miss regular and supplementary immunisations.

Based on these learnings, Khan says, Pakistan has identified areas and population groups with different levels of risks and thereby allocated adequate resources, implemented immunisation campaigns, and made community engagements.

Jan believes Pakistan can be declared polio free with “sustained political commitment, quality focussed vaccination campaigns, and ​improved expanded programmes on immunisation and accountability.”

Meanwhile, for Shakeel and her door-to-door efforts, the task of “winning the trust” of people continues.