Portside

Part 1

We are an hour or so east of Jalalabad, in eastern Afghanistan, when our Land Cruisers turn off the main highway and head toward a line of mountain peaks that marks the border with Pakistan. We pass a sandbagged machine-gun nest manned by Afghan cops, who glance at our white-painted vehicles with placid interest. There are two police pickups escorting us; at night this area is controlled by the Taliban, and even during the day they are watching.  Soon we arrive at Lal Pura, a little Y-shaped bazaar of pharmacies, bakeries, and general stores straddling a fork in the road. Our convoy has come to hunt an enemy hiding in the mountainous terrain between Afghanistan and Pakistan. But we are unarmed, and the doors of our vehicles are painted in blue block letters: who and unicef. The adversary is the poliomyelitis virus, and the international delegation of doctors I am traveling with are at the forefront of a billion-dollar global battle to eradicate it from the planet.  We pull into the Lal Pura health center, a compound of rudimentary one-story concrete buildings that provides basic medical services for the district, which extends roughly 10 miles east to the Pakistani border. The clinic staff comes out to greet us, receiving Ali Zahed, head of the World Health Organization's surveillance program in Afghanistan, with particular warmth. Before he joined who, Zahed worked for the Afghan government, heading the polio program in the eastern end of the country, and he knows most of the staff in the districts personally, knows the hardship and danger that they face working in the mountains. Zahed is short, with a square jaw and slightly hooded eyes that combine with his pointed eyebrows in a variety of deadpan expressions-he's a natural joker. But his face is serious now as he listens to the local staff; Lal Pura is a big problem for him and the polio campaign.

The border regions between Pakistan and Afghanistan are wracked by violence, and their rural hinterlands are largely under the control of a diverse array of militant groups. The Taliban in Afghanistan have been mostly cooperative with the polio campaign-in the south of the country, where their writ is strongest, they even help point out areas missed by vaccine teams-but in 2012 Taliban leaders in Pakistan began banning vaccinations in their areas, condemning the campaign as an American plot. They also started targeting campaign workers for assassination: Since the ban started, 22 people have been killed in attacks on vaccine teams.

Here in eastern Afghanistan, the influence of the Pakistani Taliban is strong. In Lal Pura, six villages-representing 200 of the district's 1,100 households-have been off-limits to polio campaign vaccinators for the past two years. Pakistani militants have been living nearby, and they refuse to let the vaccine teams in. The result is a pocket of unvaccinated children and a reservoir for the virus-one that threatens to spread to the entire region if unchecked. Indeed, seven months earlier, one of the few cases of polio paralysis in the country was reported here.

    In Pakistan, 22 people have been killed in attacks on the vaccination program.

As we stand in front of the clinic's main building, the screen door swings open and a 6-year-old boy, the son of a nurse at the clinic, walks out and stands staring shyly at the knot of strange men.

"Ah, here is our case," Zahed says, smiling at last and tousling the boy's hair. He has fortunately made a full recovery. But other children in the border regions will not be so lucky. And unless the polio teams can get access to them, the virus will continue to circulate. The global campaign, decades in the making, has come down to this: an all-out, very expensive effort to eliminate the last few problem areas in some of the most troubled and undeveloped parts of the final three countries where polio is endemic: Afghanistan, Pakistan, and Nigeria. It is one of the most expensive and ambitious global health initiatives today, and it is tantalizingly close to victory. There are now just a few hundred cases of paralysis per year worldwide, down from roughly 350,000 when the campaign started in 1988. But going the final inch will require more than just good science and vast amounts of money-it will require a tremendous force of collective will.

Part 2

A vaccine team at the Torkham border crossing between Afghanistan and Pakistan.
 

Only one human disease has been eradicated to date, and it was arguably the most prolific killer in history: smallpox, a virus that brought death to a fifth of its victims and horribly disfigured the rest. Beginning in earnest in 1966, under the leadership of an American epidemiologist from the US Centers for Disease Control, Donald Henderson, WHO succeeded in eliminating smallpox by vaccinating more than 80 percent of the world population. But the lengths to which Henderson's team had to go to carry out this feat illustrate just how arduous and risky eradication is. To snuff out the disease in the Eastern Bloc and Southeast Asia, they had to strike up partnerships with Soviet officials at the apex of the Cold War. The campaign enlisted regimes and warring tribes to treat millions of people in 23 smallpox- ridden African countries. At one point, both sides in the shooting war between Nigeria and the Republic of Biafra (a short-lived secessionist state in Nigeria's southeast) agreed to a brief ceasefire so that vaccines could be transported. By the end of 1975, the disease persisted only in the Horn of Africa; it took two years of frantic work to keep it from escaping and to find the final cases. The very last naturally occurring case, a hospital cook in the Somalian town of Merca, was identified and isolated on October 31, 1977. (That man survived and went on to become a vocal leader in Somalia's polio eradication campaign until his death in July of this year.)

The smallpox campaign represented a new kind of success brought about by cooperation on a global scale, one that permanently made the world a better place. Researchers studying smallpox are the only people who have to be vaccinated against it anymore. It's gone. With that success behind them, public-health officials naturally wanted to repeat it with other diseases. After a 17-year campaign, a cattle infection called rinderpest was officially eradicated in 2011. But the struggle to eliminate a second human affliction has proved more difficult than anyone imagined. Yellow fever seemed like a candidate until researchers discovered that the virus also infected primates, which meant eradication couldn't succeed without vaccinating nearly every monkey and ape in the jungle. Similarly, an expensive malaria eradication effort foundered on technical challenges and was abandoned in 1978.

UNICEF representatives observed vaccinations in Lal Pura, where one of this year's polio cases occurred, and the Torkham border crossing between Afghanistan and Pakistan.

Polio, because there's an effective vaccine for it and because it's restricted to humans, also looked like a promising target. By 1988, when WHO and a coalition of governments decided to attack it, the disease had been largely banished from Europe and North America. And yet smallpox, fearsome though it was as a killer, was actually easier to eliminate than polio. This is because-unlike smallpox, which struck its victims with visible pustules and scars-polio is largely invisible, making it far more difficult to track and eliminate.

The poliomyelitis virus has likely been living with humans for millennia. Archaeological excavations of prehistoric burial grounds, as well as paintings in ancient Egyptian monuments, show limb paralysis that is probably the result of polio. The virus, part of the enterovirus genus, is extremely contagious and spreads through two routes-oral-oral, through saliva, or more commonly fecal-oral, like when an infected person's feces contaminate the water supply. In the crowded, unsanitary cities of antiquity and medieval times, this meant that virtually everyone would have been exposed to the virus in childhood. For most people, this wasn't a problem: The virus typically infects only the mucosal tissues of the gastrointestinal system for a few weeks, where the immune system clears it before any harm is done. After that, the infected person would be immune to future infections from the same strain. However, in less than 1 percent of infections, the virus attacks the central nervous system and causes paralysis. Typically this affects just the legs. But in 5 to 10 percent of paralytic cases (that is, 0.05 percent of total infections), polio paralyzes the breathing muscles, meaning that without artificial respiration the patient will suffocate.

All this explains why polio is so difficult to annihilate. For every one person who actually gets sick, nearly 200 are carrying the virus and infecting others. To detect the spread of the disease in Afghanistan as soon as possible, Zahed and his colleagues have built a network for reporting suspected cases of polio-related paralysis. Since Afghanistan's public health care system is almost nonexistent in many rural and remote areas, they've recruited all sorts of locals to whom parents are likely to bring a sick child: mullahs, shrine keepers, pharmacists, faith healers, and traveling quacks. They've been given basic training and are paid a reward of about $5 for reporting a confirmed case of paralytic polio. Moreover, advances in rapid genetic sequencing have allowed researchers to chart the path of each infection, showing the complex and often unexpected ways in which polio can travel.

Despite such advances, though, the invisible nature of most infections means that areas thought to have been cleared can flare up again with little warning. For example, this year tests of sewage in both Israel and Egypt, which had been deemed polio-free, revealed polio virus that was descended from a strain detected in Pakistan-even though no symptomatic cases have yet been reported in either country. To prevent a return of the virus, population immunity levels need to be kept very high-above 90 percent. And every year, a new cohort of unvaccinated children is born. Unless they are vaccinated, a susceptible population can build, ripe for a return of the virus. In Somalia, polio transmission was stopped in 2007, but fighting between Islamist groups and the Western-backed government in recent years has rendered large areas of the country inaccessible to vaccination programs. The polio campaign watched nervously until finally disaster struck with a new outbreak in May, with nearly 200 cases this year, and some reported in Ethiopia, Kenya, and South Sudan as well. In October, who announced that it was investigating a cluster of possible polio cases in Syria, where the conflict has produced more than 2 million refugees.

For all the laurels heaped upon Henderson and the generation of epidemiologists who slew smallpox, eradicating polio may be the hardest initiative that the world public-health community has ever undertaken. Based on the timeline with smallpox, the original vaccination plan in 1988 was that polio would be gone by the turn of the millennium. But in 2000 there were still roughly 700 confirmed cases of polio paralysis worldwide, and the disease remained stubbornly entrenched in Africa and South Asia. Now, 13 years later, the target date has been pushed back to 2018. Reaching that goal depends on the vaccinators who go door to door in the world's most unstable regions, trying to immunize nearly every child.

Part 3

In August, I traveled to Jalalabad to observe one of Afghanistan's quarterly National Immunization Days, a three-day span during which the campaign attempts to deliver vaccine to every child under the age of 5. Some 60,000 vaccinators will visit 4.3 million homes and immunize 7.8 million kids, from the scorching deserts of Nimroz Province to the high-altitude valleys of the Wakhan Corridor. Here in Jalalabad, roughly a quarter of the immunization push is overseen by Rana, an unlikely warrior in a region ruled by men with guns: 5 feet tall and slight of build, with a powder-blue burka pulled over her head and high-heeled, glittery sandals peeking out from under its hem. At age 25, Rana will be responsible for managing seven teams of two women apiece, slated to vaccinate 13,952 children in all.

I first meet Rana on the eve of the Immunization Days, at the local campaign headquarters in the Jalalabad hospital. Zahed teases her as she walks by, burka pushed up on her forehead. "Hey, Commander, where are your soldiers?" he asks.

    Although cases dropped after the fall of the Taliban regime in 2001, an outbreak in 2011 brought 80 new cases and a general sense of emergency.

"They'll be ready!" she shoots back. "Tomorrow is a big day."

Because all the Afghan polio cases in 2013 have been reported here in the eastern half of the country, these National Immunization Days have special importance in this region. As with the global campaign writ large, polio here has receded greatly over the past two decades but with serious setbacks along the way: Although cases dropped after the fall of the Taliban regime in 2001, an outbreak in 2011 brought 80 new cases and a general sense of emergency. And so the eradication program-which is government-run but supported financially by who and unicef -ordered a "surge" in Afghanistan. They doubled the international staff and cracked down on underperforming and corrupt officials. This year, the surge has paid a huge dividend, in that the war-torn south of the country, for a long time the greatest problem area, now appears to be free of the virus. It's the inaccessible areas in the east, where Jalalabad is, that are now the main concern.

The next day, Rana and her team leaders arrive at the polio headquarters and start packing the navy-blue cylindrical carriers-they look a lot like insulated lunch bags-that they'll take into the field. Each carrier holds roughly a dozen vials of polio vaccine, along with cold packs, applicator nozzles, and, as a bonus, a jar of fruit-flavored deworming tablets. The team leaders load into the waiting vans, and Rana follows behind in a Corolla, chauffeured by her driver. Within the safer confines of the city, all of the vaccination teams are female, which is more effective, since strange men are forbidden from entering domestic spaces.

Vaccines must always be kept cold, from their flight to Kabul to scattered vaccine distribution points to the blue coolers vaccinators carry to children's homes.

Rana's father is elderly, and she doesn't have any brothers, so it has fallen to her, as the oldest daughter, to be the main breadwinner in the family. She graduated from teacher's college but has been unable to find a full-time job in a school. In the conservative segments of Afghan society-which describes all but a tiny slice of the elite and the urban upper-middle class-it's considered a bit disreputable for a woman to work outside the home, especially in a job that involves going door-to-door. So Rana and her colleagues are mostly here out of financial necessity. Not that they get paid much-the vaccinators earn the equivalent of $3.50 a day, whereas a male laborer makes at least $6. Even as a supervisor, Rana earns only about $4 a day.

She heads out to check on a team in a suburb of the city. Eventually we spot them standing near a gaudy mansion the locals have dubbed the White House. Next door lies a set of interconnected mud hovels bordering a sewage ditch that bubbles slowly, its surface covered in ropes of black algae and crowded with flies. Three ducks float in the ditch, snuffling at the scum. Further down, shrieking children scramble barefoot through the mud and splash in the water. It's easy to see how the fecal-oral route works here.

As Rana and her team go into the mud dwellings, an older man comes out and stands beside me on the edge of the ditch. His name is Ali Mohammed, and his family lives in just one of the single-room hovels. He has a long black beard, and he twists it as he talks. Twenty years ago, he says, he came from a rural mountain village in neighboring Kunar Province, looking to escape the chaos and violence of the civil war that had been sparked by the defeat of the Soviets. Now he works as a cook, earning about $80 a month, and rents the hovel. At 40, he is old enough to remember the smallpox eradication campaigns and approves of the polio one. "Allah Almighty provides us help, but this is his means," he says.

The Economics of Eradication

Experts disagree about the wisdom of eradication. This chart illustrates the critics' concern: As cases dwindle, the amount spent per reported case skyrockets to almost $2.5 million in 2012, money that could be used to treat and prevent thousands of cases of cholera or TB.

But this second chart shows the supporters’ logic. Polio costs an estimated $1.5 billion a year just to keep in check. After eradication, spending would drop to nearly zero—forever. — katie m. palmer

Infographic by Thomas Porostocky; Source: Kimberly Thompson and Radboud Duintjer Tebbens, Kid Risk

Part 4

The eradication campaigns follow a necessary logic. As the smallpox precedent shows, once you have beaten back a disease to just a few hundred cases, they will almost by definition be concentrated in places where there's some barrier-geographical, cultural, political-to easy vaccination. In general, each marginal case will cost more, and will consume more time and effort and labor, than the one before it. This hockey-stick curve was true of smallpox, and it's proving to be true of polio.

Robert Steinglass, who directs an immunization project funded by the Bill & Melinda Gates Foundation, points out that for the past 10 years, 90 percent of the $300 million annual vaccination budget for WHO in Africa has gone to the eradication of polio-which now afflicts only a few hundred people per year. More than $1 billion is spent on the polio campaign each year. By comparison, the Global Fund to Fight AIDS, Tuberculosis, and Malaria-diseases that kill approximately 3.2 million people each year-is seeking $15 billion in funding through 2016.

For every 200 people infected with the polio virus, one is paralyzed. Polio victims young and old are fitted for leg braces at Jalalabad's Nangarhar Regional Hospital.

Is the polio campaign worth it? I pose this question to Steven Rosenthal, an epidemiologist at the CDC who is visiting Jalalabad to observe the National Immunization Days. He's been working on polio since 1995, when the CDC sent him to Indonesia to work on the campaign there. Though Indonesia ended transmission by 2006, the reality that the campaign would be a long haul began to weigh on Rosenthal then, especially when faced with the major setbacks in South Asia and Africa. "At the time," he recalls, "I worried that the problems were too complex to ever be solved." But, he goes on, the teams in these regions-particularly in India, which eliminated transmission in 2011, an enormous success story by any standard-learned how to solve the worst of their problems, which centered around vaccinating an extremely dense and impoverished population by means of a corrupt and barely functioning health care system. The key was getting above that 90 percent immunity threshold, and they did it. In Rosenthal's mind, that was the turning point in the campaign, and recent setbacks-like the one in Somalia-have been relatively minor by comparison.

Against critics who blanch at the cost of eradication, Rosenthal counters that the polio campaign is paying dividends throughout the global health system. In Afghanistan, as elsewhere, the initiative is training a generation of health care workers like Rana in modern, goal-oriented public health practices: the cold-chain system, for example, as well as those new techniques in molecular epidemiology. In Indonesia, Rosenthal points out, "the polio lab network we built wound up forming the backbone for their measles campaign. Working on the polio campaign changed the way their public health officials work."

Moreover, the math of cost-benefit analy-ses runs aground when it comes to eradication campaigns, because the benefits, in theory, are infinite. That is: No one will ever die from-or spend a dime on vaccinating against-smallpox for the remainder of human history, barring a disaster involving one of the few lingering military stockpiles. According to a 2010 study, polio eradication would generate $40 billion to $50 billion in net benefits by 2035. Looking at a long enough timescale, the eradication of polio could someday be seen as positively cheap.

Part 5

In recent months, the political climate for the campaign along the border has improved, at least on the Afghan side. The main leadership body of the Afghan Taliban, known as the Quetta Shura, issued a statement in support of the campaign in May. And at the Lal Pura medical center, Zahed and his delegation receive good news from those six villages, the ones that previously had refused vaccination. Two polio staffers, dressed in traditional robes and pantaloons, show up from the valley to explain. It turns out that after an unrelated dispute, the local Taliban kicked the Pakistani Taliban out, and with those militants gone, the villagers persuaded local leaders to allow vaccination. Everyone looks relieved to hear this, especially Zahed.

Now his biggest problem, while the global campaign waits for a resolution of the ban in Pakistan, is to prevent the disease from crossing back over the border. Attacks on polio workers there have continued-a vaccination center in Peshawar was bombed in October, killing two people and wounding at least a dozen others. The most worrisome locus of all is North Waziristan, a region in Pakistan's tribal areas where the Taliban commander, Hafiz Gul Bahadur, has forbidden any polio vaccination campaigns since 2012, demanding that the US end its drone campaign in Pakistan before he relents. Today, researchers estimate that more than 160,000 children in North Waziristan have gone unvaccinated in the past year alone. The inevitable outbreak there is already under way and has spread beyond the province; the Federally Administered Tribal Areas (which include Waziristan) and the neighboring province of Khyber Pakhtunkhwa have had 38 paralysis cases in 2013, or nearly 90 percent of Pakistan's cases for the year. If children there can't be vaccinated, it will be almost impossible to stop the virus from spreading into Afghanistan and neighboring areas-and perhaps to other parts of the world.

    Today, researchers estimate that more than 160,000 children in North Waziristan have gone unvaccinated in the past year alone.

On the same day we visit Lal Pura, we take a trip to the Torkham border crossing, one of the largest crossing points between Afghanistan and Pakistan. It's a narrow opening between spindly rock outcroppings; twin outposts stand opposite one another, bearing their respective flags. Long lines of trucks wait to enter and exit the country-many of them bringing supplies into Afghanistan for the US military or ferrying equipment out-while on either side a constant stream of pedestrians flows, as taxis and buses are not allowed to cross the border. A bewildering mix of humanity streams through: Punjabi businessmen in suits, Farsi-speaking officials, students in uniforms with blue Unicef backpacks who cross each day for school, whole Pashtun families from the border tribes, the men swathed in elaborate turbans and women in burkas carrying armloads of children. No one checks any of their documents. If we disguised ourselves as locals, we could walk right into Pakistan, or back again, potentially carrying the virus with us.

The polio campaigners have set up on both the incoming and outgoing sides in Afghanistan. Women and children are usually ferried, like baggage, by porters with pushcarts; the polio workers intercept the carts, guiding them off to where the vaccinators wait like pit-stop crews. We watch as a porter wheels up a cart with several kids on their mothers' laps, eyes lined with dark kohl and hands painted with henna.

The local staff passes one of the vials to Rosenthal. He steps forward, pinches a small girl's cheeks, and squirts two drops in her mouth. As the child is wheeled away, she looks unsure whether to laugh or cry. She seems to blink in astonishment, as we all should, at her brush with the most ambitious health campaign in history, a billion--dollar machine that is learning-hopefully well enough and fast enough-how to reach every single child in the world's most unreachable places.