A health worker in Karachi administers polio drops — the oral vaccine — on February 3, the first day of a nationwide polio vaccination campaign. The country, one of only two where wild polio circulates, has seen a rise in cases due to issues with vaccination campaigns.
Asif Hassan/AFP via Getty Images
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Asif Hassan/AFP via Getty Images
The world is so close to wiping out polio. But in 2025, there are sign that the virus is not quite ready to go the way of smallpox — the only disease eradicated by humans.
Two countries are seeing an increase in cases caused by the wild polio virus, which can cause paralysis and even death, particularly in infants and young children.
And the cuts in USAID contracts that support polio vaccination raise concern that other countries will see a resurgence as well.
Even with in-country vaccination campaigns and global aid, Pakistan and Afghanistan have so far been unable to stop transmission of the disease. In 2024, Pakistan’s numbers spiked to 74 while Afghanistan saw 24 recorded polio cases. So far this year, Pakistan has reported 6 cases and Afghanistan has reported 1. These new cases are tied to disruptions in ongoing vaccine campaigns.
Global health officials say there’s real concern that those numbers could balloon and that polio could reemerge in other countries as well in the wake of the dismantling of USAID. In a series of memos drafted by Nicholas Enrich, the acting assistant administrator for global health at USAID, and obtained by the press, including NPR, the potential for damage is quantified with estimates of how many people would possibly become sick and die if the pause in U.S. aid continues. Enrich projected an additional 200,000 cases of polio that cause paralysis each year, and hundreds of millions of infections overall.
“The sudden cuts to U.S. funding are also affecting efforts to eradicate polio,” said director general of the World Health Organization Tedros Adhanom Ghebreyesus in mid-March.
In Kenya, for example, the International Rescue Committee was part of a team doing polio vaccinations along with the Ministry of Health and World Vision. Much of that work was paid for by USAID.
“That actually was the first [of our USAID projects] to shut down on the 31st of January,” says Mohamed El Montassir Hussein, country director for the International Rescue Committee in Kenya. “Currently IRC’s support for polio vaccination in remote areas has stopped [because of the halt in U.S. funding] and future support is in question. The Ministry of Health vaccination efforts, though greatly impacted, continues.”
As for Afghanistan and Pakistan, the numbers there, while relatively low, raise the question: Why does the wild virus persist in these two countries when it’s been eradicated from the rest of the world since 2020? (Other countries have experienced cases of vaccine-derived polio, which can occur when the weakened virus in the oral vaccine mutates and regains its ability to cause paralysis).
Here is a look at what is happening in Afghanistan and Pakistan.
Why Pakistan is seeing a resurgence
Usman Ali, a 2-year-old, is one of 74 children in five Pakistani provinces known to have contracted polio in 2024. He is now experiencing partial paralysis.
“[I fear] my youngest son will not be able to walk or play for the rest of his life,” says his mother, Naik Margha.
Ali lives in Balochistan province, bordering Afghanistan. When polio workers came door-to-door in late April last year in his village of simple mud and brick houses, the child had a fever. His parents worried the vaccine would make his illness worse, so they refused it. They asked polio workers to mark his finger with purple ink anyway to make it look like he’d been vaccinated.
Ali had fevers on and off for several weeks, and in June, began having trouble walking. His parents rushed him to a private clinic for treatment. When a later test of his stool sample came back positive for polio, they realized it was paralysis and could be permanent. Since then, Ali has recovered somewhat but still has partial paralysis in one leg.
Ali’s community is comprised of seasonal migrants who travel yearly to herd their sheep, mostly in the plains of neighboring Punjab province. Their village lacks toilets and sanitation, and people defecate in the open, which health officials say puts around 2,000 other children at risk of contracting polio, which can be spread by contact with human waste.
“This is a vulnerable community. They can easily carry the virus from one place to another place,” says Saeedullah Lawoon, a polio community communication officer in the district.
Polio has surged despite Pakistan’s extensive surveillance program and repeated door-to-door vaccination campaigns, highlighting shortcomings in the country’s polio program. Pakistan has struggled to maintain the necessary high rates of immunization while combating vaccine fatigue.
To be optimally protected from polio, health care experts recommend that children in Pakistan receive two doses of the injectable vaccine and at least three doses of the oral — an aggressive course aimed at interrupting transmission. In 2023, only 84% of the country’s eligible children received two doses of the injectable vaccine, according to World Health Organization and UNICEF estimates shared by the Pakistan Polio Programme. while 86% of children received three doses of the oral vaccine during routine immunization.
“We have higher coverage in Punjab overall, but very low coverage in Balochistan, parts of Karachi, parts of South Khyber Pakhtunkhwa, parts of Balochistan and even Southern Punjab,” says Dr. Hamid Jafari, the WHO director of polio eradication for the region. “[There is] huge provincial variation. Punjab is 60% of the country, so it can skew the national average.”
Vaccination rates during door-to-door drives can surpass 90%, according to Pakistan Polio Programme data, but these campaigns only offer the oral vaccine. To receive the injectable vaccine, parents must travel to designated facilities. The injectable vaccine is harder to administer and requires trained health workers and sanitary conditions. The result is that some children in Pakistan only receive the oral vaccine, while some aren’t vaccinated at all.
More than half of the polio cases in Pakistan last year were from children who hadn’t received a single dose of either version of the vaccines. The other 45% were children who had received the oral polio vaccine, sometimes up to seven times, according to case data. Experts say receiving that many doses is not dangerous for a child. Pakistan’s Polio Programme says what’s important is that every child is vaccinated during each vaccine campaign to maintain their immunity.
Pakistan’s polio eradication program was started in 1994 and made strides early on to significantly reduce the number of polio cases in the country, which used to be in the tens of thousands. Between 1994 and 2013, the country managed to reduce the average number of annual cases by around 96%, from 2,635 to 93. Case numbers seesawed in the following years before reaching an all-time low in 2021, when Pakistan recorded only one infection
Although cases have fluctuated in the past, experts say last year’s increase was particularly alarming. Zulfiqar Bhutta, founding director of The Institute for Global Health and Development at the Aga Khan University in Karachi, says there’s also not one reason why.
“It isn’t one single factor that leads to polio exacerbations, ups and downs in Pakistan. It’s always a combination,” he says.
Bhutta attributes the spike in part to laxity with door-to-door vaccination campaigns. In some cases parents or health workers will mark a child’s finger who hasn’t been vaccinated, which he attributes to fatigue among health workers under pressure to hit vaccination targets and exhausted from dealing with uncooperative parents. He also cites inadequate supervision of vaccine workers on the ground.
Then there’s vaccine distrust — still a problem in parts of Pakistan and in neighboring Afghanistan. Some think the vaccine will affect fertility, while others believe vaccines are part of a Western conspiracy. The distrust of aid workers grew after the CIA operated under the guise of a vaccine campaign to search for Osama Bin Laden in 2011.
Polio workers also struggle to access certain areas because of conflict and security risks. In the past decade, they’ve become the target of militant groups who accuse them of being government spies or agents of the West.
In some cases, parents refuse vaccines for their children because they’ve grown tired of repeat visits by polio workers, who are required to give oral polio drops during each vaccination campaign to every child under the age of 5 — including those who’ve received them multiple times before.
According to a September 2024 report by the Independent Monitoring Board of the Global Polio Eradication Initiative, over four million Pakistani children missed being vaccinated last year.
Polio spreads quickly within unvaccinated communities, and mobile populations carry the virus from one part of the country to the next. People also bring it with them across the border from neighboring Afghanistan.
In the past, both Afghanistan and Pakistan have each come close to eradicating the virus, says Dr. Jafari of WHO. But the two nations’ vaccine campaigns didn’t align, so pockets of polio can persist and spread between the countries.
“It’s been very difficult to find a time period where the progress was well synchronized so that they both would interrupt transmission at the same time,” he says. “Polio is an epidemic-prone disease. That means that if you don’t interrupt transmission, it resurges after every few years.”
A number of recent cases involve children who avoided severe paralysis, thanks to some level of protection from oral vaccines, says Zia Ur Rehman, spokesperson for the Pakistan Polio Eradication Programme. “That is very encouraging. And it shows that there is always a benefit of repeated vaccination.”
Pakistan held its first vaccination drive of the year in early February in an attempt to ensure that all children under age 5 have received at least one dose of the oral vaccine, with the goal of eventually achieving herd immunity. This should occur with polio when around 80% of the population is vaccinated, although Pakistan presents a special challenge.
There’s no clear threshold for herd immunity in Pakistan, according to WHO’s Hamid Jafari. “There isn’t just one figure that we can go with in terms of what level of immunity do you need to stop transmission.” He said the 80% rate might be an average figure for countries with better sanitation and less population density, but in South Asia, higher vaccination rates are needed to interrupt transmission.
The campaign aimed to reach about 45 million children around the country. According to Pakistan’s Polio Programme, health workers vaccinated about 200,000 fewer children than the target, though it’s difficult to independently verify. The number of children nationwide who didn’t receive the vaccine because family members refused was around 66,000, according to Pakistan Polio Programme data. The next countrywide vaccination campaign is set to take place in April.
Meanwhile, the virus has been detected in sewage samples around the country this year, including in Punjab province, home to around half of Pakistan’s children. Before a case was confirmed there last year, the province had been without a case of polio since 2020. Punjab has had one polio case so far in 2025.
Bhutta said the widespread circulation of the virus means the situation could quickly spiral into something much worse.
“This is like sitting on the top of a volcano. This can erupt anytime.”
Changes in vaccination strategy leave some children behind in Afghanistan
A few months ago, a 35-year-old Afghan businessman named Mohammad noticed that his youngest son’s hand looked extremely thin and was bending at an unnatural angle. A few tests later, he and his wife’s worst fears were confirmed: “We were told he was infected with the polio virus,” he tells NPR. “We missed his vaccines, and now a part of his hand is paralyzed.”
Mohammad, who requested his full name be withheld fearing reprisal for criticizing the Taliban government, blames his son’s condition on the decision to suspend door-to-door vaccination campaigns.
An Afghan health worker administers polio vaccine drops to a child during a polio vaccination campaign in Kandahar on December 23, 2024. The Taliban suspended door-to-door campaigns.
Sanaullah Seiam/AFP via Getty Images
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Sanaullah Seiam/AFP via Getty Images
In August 2024, the Taliban announced a temporary suspension of door-to-door vaccination campaigns across the country. No official reason was provided; however, health workers familiar with the situation said that the ban was a result of suspicion of Western aid and the Taliban’s restrictions placed on women workers, who aren’t allowed to travel without a male legal guardian.
“They stopped the health workers from coming to the communities, and instead moved the vaccinations to the local mosques,” Mohammad says.
Mohammad, who has four other children who are vaccinated and healthy, says that campaign suspensions coupled with the Taliban restrictions made it hard for his family to get the children vaccinated.
“As a sole breadwinner, I travel a lot for work, and the women in the family can’t just walk to the local mosque to get vaccines,” he says, referring to the Taliban’s ban on women’s movement.
Although the number of polio cases in Afghanistan is significantly less than in Pakistan, the spike was “extremely high” in 2024, according to health officials –- 24 cases compared to just six the previous year.
“The main reason for this increase is the poor quality of vaccination campaigns, particularly the lack of house-to-house distribution system which has been very successful in the past,” says an Afghan health official who requested anonymity, fearing Taliban backlash.
The spread is alarming, he says.
While Pakistan and Afghanistan remain the only countries that have failed to eliminate the polio virus, Afghanistan had made some progress in reducing cases in recent years.
However, the various Taliban groups in the region have long held suspicions that the door-to-door vaccination programs involving Western aid might be used to spy on communities.
As a result, for many years during its war with the U.S. forces in Afghanistan, the Taliban refused to allow immunization campaigns in areas they controlled. When the Taliban took over Afghanistan after the U.S. withdrawal in 2021, health workers had hoped they could finally be allowed access to previously unreachable parts of the country.
Instead, the Taliban expanded their ban across the country.
Vaccination drives have also been hampered by the Taliban’s successive bans on women’s employment across various sectors, including in NGOs and development work.
“Women are crucial to such campaigns because in a conservative country like Afghanistan they would be more welcome by families and communities with women and children, unlike the men, which allows them to not only provide vaccines and raise awareness but is also crucial to reporting some of the cases,” the health official explains.
Children wait to receive polio vaccination in Nangarhar province, east Afghanistan, in November 2024 — part of a three-day campaign kicked off in 11 out of Afghanistan’s 34 provinces that month, according to the Ministry of Public Health. Sharafat Zaman Amarkhail, the ministry’s spokesperson, said 5.3 million children under age 5 were expected to receive vaccine doses during the campaign.
Aimal Zahir/Xinhua via Getty Images
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Aimal Zahir/Xinhua via Getty Images
Instead, he says, the remaining, mostly male, health workers have been advised by the Taliban to conduct campaigns in mosques across the country, where families are expected to bring their children for doses.
“This leaves many children unvaccinated since most families aren’t aware or proactive about getting vaccines,” the health official says, adding that for the vaccines to be successful, at least 95% of children under the age of 5 need to be covered during each campaign.
“For most families experiencing poverty, polio vaccine is not a priority,” he points out. According to U.N. estimates, more than half the Afghan population relied on humanitarian assistance in 2024 from charities like the U.N.’s World Food Programme.
And in densely packed areas with limited sanitation, many children are already struggling with health issues that make them more vulnerable to polio.
“Immunity among children is low and there are other diseases like diarrhea, malnutrition that is also spreading, alongside a lack of hygiene and sanitation which makes it a deadly combination,” he says.
Afghan health workers say they are continuing to advocate, alongside international organizations, to resume door-to-door campaigns. In the meantime, health care workers are encouraging parents to bring their children to local vaccination centers.
“If we don’t act now, we may be faced with many tragic cases across the region, because infections don’t see borders and can spread fast,” the health official warns.
For Mohammad’s youngest son, though, it might already be too late.
“All my children except the little one were vaccinated at home. I appeal to the [village] elders to [negotiate with the officials to] resume the door-to-door vaccinations again because not every family can travel to a public space and get the vaccines,” he says. “It is not a matter of just my family or province, we are talking million of innocent children who are at risk.”
Betsy Joles is a journalist based in Pakistan.
Ruchi Kumar is a journalist who reports on conflict, politics, development and culture in India and Afghanistan. She can be found on X at @RuchiKumar
