The end of polio

On 11th August 2014, the last ever case of polio in Africa was reported in Somalia. After a three decades-long global programme to eliminate the disease for good, the end is now in sight.

Somalia had thought it was clear—there had been six years without cases—when, in May 2013, a two-year-old girl in Mogadishu woke one morning unable to walk. That year, 194 Somalians contracted polio. But in 2014, the number fell to just five. Since then the disease has vanished from Africa, wiped out not only in Somalia but also Nigeria, where it was endemic.

This success means that polio, a disease that for centuries has killed, paralysed and disfigured children, is on the verge not only of eradication in Africa, but of being extinguished worldwide. A huge programme led by governments and international humanitarian agencies, costing billions of dollars has almost wiped it out—and if that goal is reached, the savings will also be in billions. The disease was once so prevalent that the National Health Service estimates that 120,000 people in Britain are still living with the withered, paralysed limbs and other after-effects of the disease. British children are still vaccinated against polio, which they receive by injection aged three.

Now polio is confined to a narrow strip of land on the border of Pakistan and Afghanistan, where a huge effort is underway to eliminate the last remaining virus. Experts predict that global eradication will be achieved within five years. If so, that will be only the second time in history that medical science has eliminated a disease from the human population. The other was smallpox, in 1980.

As recently as the late 1980s there were more than 350,000 reported cases of polio a year, across 125 countries—1,000 children per day were contracting a disease capable of crippling them for life. Since 1988, there has been a 99.9 per cent global reduction in polio, and by 2014, there were fewer than 400 cases worldwide, an astounding reduction. So far, in 2015, there have been just 34 reported cases of polio worldwide, all on the Pakistan-Afghanistan border.

It is perhaps not surprising that the last remnants persist in one of the most dangerous parts of the world. But these final cases cannot be ignored—so long as the disease exists anywhere, it has the potential to spread.

Poliomyelitis is a highly transmissible disease caused by a virus, and the most common form of transmission is through faecal matter in contaminated food or water. This makes polio extremely difficult to contain in areas with poor sanitation, where it tends to thrive. Once the disease gets into a population, it is very hard to get it out again. So long as eradication is incomplete, the threat of future outbreaks remains—and the successes of the last 30 years risk being lost.

An unusual characteristic of polio is that most people who contract it experience no symptoms and it is not known why some people are more susceptible than others. Around 5 per cent will experience only mild symptoms, usually a fever. But in a small number—less than 1 per cent—of cases, the virus will attack the neuron cells in the spinal cord, infecting and killing those cells. The most common result is a paralysed limb, which over the years becomes stiff and disfigured. Polio can paralyse any muscle in the body, including the muscles of the diaphragm used for breathing. Between 5 and 10 per cent of people who develop paralysis will die.

The headaches and muscle pain of the polio fever can be intense and parents’ first indication that their child is suffering can come when they try to pick up the infant, who screams in pain. In Living with Polio, Daniel Wilson describes the onset of the disease in a young boy who stayed at home from school one day and went to bed with that he “thought was a cold with a fever.” Later when he tried to get out of bed, he “fell on the floor and... couldn’t get up.” His limbs became limp, and his legs gave way from under him when he tried to walk. In the 1920s, death rates in the United States were as high as 60 per cent among sufferers’ whose breathing muscles became paralysed.

There are three varieties—or serotypes—of poliovirus, and though they differ in their genetic make-up, the paralysis caused is the same. The most significant difference is in their effects. Type One—the most widespread strain—is the worst; around one person in every 200 develops full paralysis. Only one in a thousand who catches Type Two or Three will be paralysed. People who contract polio are then immune from it, so the disease tends to afflict young children, who are least likely to have developed this natural immunity. Type Two has been absent since 1999, when it was last identified in northern India. Type Three was last seen in November 2012. All that is left is Type One, the most aggressive strain.

Evidence of the disease is scattered through history. An Egyptian carving from 1,000BC of a priest with a withered leg is thought to be the first depiction of polio. The science of viruses was not understood until the late 19th century and it was not until 1909 that the virus was first isolated and identified. At the time, polio was endemic. In the early to mid-1900s, levels of paralysis in the US peaked at 40-50,000 cases a year (among them the future President Franklin Roosevelt). Fear of polio in the US meant that in the summer months, when outbreaks hit their peak, swimming pools were closed, large gatherings were discouraged, and warning signs were put on the doors of infected houses. In Britain during the late 1940s, there were up to 8,000 cases a year.

And then, by the 1970s, polio all but vanished from the developed world. The US has not had a reported case in 30 years. The final outbreak in Britain occurred in the late 1970s and the last known case of polio infection acquired in the United Kingdom was in 1984. This staggeringly rapid success was down to the development of powerful, cheap polio vaccines. An injectable variety, developed by Jonas Salk, the American virologist, was licensed in 1956 and based on a “killed” form of the virus, meaning that it contained no traces of the live virus. A second was developed by Albert Sabin, another US researcher, and licensed in 1962. Sabin’s vaccine was taken orally in the form of drops, and contained a modified form of live virus. It also cost around one tenth of the price of the injected variety and quickly became the more popular.

From the mid-1960s onwards, the vaccine was distributed widely and rates of infection declined everywhere. And yet by 1979, despite the success in developed nations, including in Britain where the vaccine was administered to children on a sugar lump, half of the children in the world were still not being vaccinated. This is a point that was not lost on John Sever, who was then head of the infectious diseases branch of the National Institute of Neurological and Communicative Diseases at the US National Institutes of Health. He also happened to be a regional governor for the Washington DC area of Rotary International, a humanitarian organisation based in the US. In 1979, Rotary had raised $7.5m from its members, and was looking for a project on which to spend the money. Its President asked Sever for a suggestion. “My response,” Sever told Prospect, “was—take on the immunisation of the world’s children for polio.” In this one suggestion, he triggered the final push to complete the global eradication of polio.

Rotary International’s first mass immunisation programme began in the Philippines in September 1979, where it spent $750,000 funding vaccines for six million children. Buoyed by this success, it turned to Latin America, where it worked with the Pan American Health Organisation, part of the World Health Organisation (WHO), to launch immunisation programmes. In 1985, Rotary launched a fundraising drive with a target of $120m; by 1988 it had raised $240m. “We were very happy with that,” said Sever, with some understatement. At that year’s WHO meeting in Geneva, health ministers from around the world, having seen Rotary’s success, voted to take the eradication of polio as a WHO global target. This had the effect of making it a health priority for all governments. Sever’s idea had gone global.

“By the early 2000s, we were basically down to four countries,” said Jay Wenger, who heads the polio eradication programme at the Bill and Melinda Gates Foundation, which has contributed funds and technical resources to the global immunisation effort. “It was India, Nigeria, Afghanistan and Pakistan. But those countries were problematic. And as long as you have [polio] anywhere in the world, there is a threat that it could leave that country and go to another country. All you would need was an unprotected kid to get on a plane.”

Of the four, India was an especially complex challenge, with its vast population, poor sanitation and crowded living conditions, a combination that led some health experts to doubt whether polio eradication was achievable.

“We have learned how tenacious and how difficult it is to dislodge in certain conditions, particularly what we encountered in India,” said Hamid Jafari, Director of Global Polio Eradication and Research at WHO. “The level of immunity that you need to dislodge it from human populations can be really extraordinary.” Unfortunately, according to Jafari, “the efficacy of the oral polio vaccine that we were using was compromised.” Advances by Jafari and his team led to the insight that combinations of vaccines can sometimes be required. The most widely-used form gives immunity from all three types; this is known as a trivalent vaccine. Combinations of monovalent vaccines—targeting just one—along with bivalent vaccines, which immunise against two out of the three types, were much more effective. It was a combination of vaccines, according to Jafari, along with reforms to the governance of Indian healthcare, that helped to achieve eradication in India. The last case was recorded in 2011.

The challenges in Nigeria, the last African country to eradicate polio, were different. “In 2004, things were floundering,” said Oyewale Tomori, President of the Nigerian Academy of Science, who oversaw the immunisation programme. During the 1980s Nigeria made progress in confronting polio, but the immunisation programme then went into decline. The scale of the problem was enormous and there was a lack of willingness to confront the disease. This changed when, in 2008, the World Health Assembly gave Nigeria “a spanking”—Tomori’s words—sharply criticising the lack of urgency in its eradication programme.

There were other problems. Rumours circulated that the vaccine rendered anyone who took it sterile. During the 2011 election, Tomori said, the Nigerian government “abandoned all programmes and spent all the money on [general election] campaigns,” a decision that “added four or five years to the eradication programme.”

Success started to come when the vaccination programme won the support of religious leaders in northern Nigeria. WHO targeted vaccinations in areas where they were most needed. Organisation and persistence has meant that Nigeria has not had a case of polio in 12 months.

Yet vaccine is still being administered in Nigeria to maintain immunity. Amina Abdulwahab is a vaccinator based in Kaduna State, in the north of the country. Though most people are happy to have their children vaccinated, there are still some, she said, who object. “I try to tell them the importance of the vaccine,” she said. “They are complaining. We convince them that the polio vaccine will be [administered] twice a month because we don’t want any virus to bring poliovirus back in Nigeria,” she says.

In the aftermath of apparent eradication, health agencies have to carry out checks to ensure that it does not return. In Nigeria, this includes monitoring territory held by Boko Haram, the Islamist militant sect that has been hostile towards the vaccination programme. In 2013, in the northern state of Kano—which borders Kaduna state—nine female vaccinators were shot dead. Though it has not claimed responsibility for the murders, Boko Haram is thought to be responsible. Nigeria’s health authorities now have to work around Boko Haram, so that as its fighters change location vaccinators enter the area vacated, vaccinate the children, and take sewage samples to test for traces of polio and retreat. “Some of us who are involved have our fingers crossed,” said Tomori. “We are working under war conditions and it is not an ideal situation… We are still not really that confident that we have done all that we need to do, especially in the areas with Boko Haram.”

The Afghanistan and Pakistan polio eradication programmes have had comparable problems with extremists. In North Waziristan, a region in Pakistan’s northwest which has a porous border with Afghanistan, the Taliban said that it would not permit polio vaccination until US drone strikes were stopped, a position that put the area out of the reach of vaccinators. This changed when, in 2014, an operation by the Pakistani army forced large numbers of people out of Waziristan and into the south. “This operation was a blessing in disguise,” said Tanveer Zubairi, President of the Federation of Islamic Medical Associations in Pakistan. Around a million people were internally displaced, and despite the problems caused, it gave vaccinators access to people who had previously been out of reach.

As in Nigeria, there was a deep suspicion of vaccinators. Rumours spread in Pakistan that they were not health workers “but people from some agency—agents who were spying on them,” said Zubairi. “That is the reason they were killing them and unfortunately polio workers have been killed in Pakistan… More than a dozen workers have been killed in the last three years.” The work itself is arduous and poorly-paid—in Zubairi’s words, they are paid “peanuts.”

“People are easily led by propaganda,” says Zubairi. “Shakil Afridi, who was alleged to be one of the team who apprehended Osama bin Laden, was a vaccination worker. This was highlighted very much in the media, [which said] health workers are being used by America or foreign countries. This is why there was resentment [from] the local people.”

WHO formed the Islamic Advisory Group, to counteract the idea that the vaccination campaign had ulterior motives. “It took us some time to pacify the local leaders,” said Zubairi. “We arranged meetings in Islamabad and other places and we told them about the composition of the vaccine and how the rest of the world had got rid of polio using these drops, including 54 Islamic countries.” Since then there has been more acceptance of the programme in Pakistan, although there are still some radical elements which are reflexively opposed to anything associated with the west, including polio vaccination. Pakistan’s eradication effort is intimately linked to that of Afghanistan, where there is also a mistrust of vaccination. “The problem is in cross-border transmission,” said Abdul Majeed Siddiqi, Head of Mission for HealthNet TPO in Afghanistan. “It is not possible to eradicate the disease till both countries do [so] together.” But Siddiqi estimates that no more than 1 per cent of Afghans are refusing to cooperate with vaccination.

Iraq and Syria had polio outbreaks last year, both of which were traced back to Pakistan. Health agencies got in to administer vaccine, and both outbreaks were successfully contained—even Islamic State allowed the vaccination of children. Other countries are at risk of outbreaks, including Yemen and Greece, as health systems are disrupted and children there are not immunised.

“Ukraine is one country that we are most worried about right now,” said Hamid Jafari of WHO. “It is at a high risk of an outbreak if there is a reintroduction of poliovirus into Ukraine from the remaining infected areas of Afghanistan and Pakistan.

“The probability of that seems to be low because we haven’t had a history of linkage between these areas. But this can change—all it takes is one infected individual coming to Ukraine and starting a chain of infection. There is a large vulnerability now in Ukraine.”

That country is now susceptible to what is known as vaccine-derived poliovirus. A child who has received the oral vaccine—which contains a small amount of adapted live poliovirus—will excrete the virus. This usually poses no risk, but in rare cases, it may reacquire the ability to infect non-vaccinated children. This form of transmission can happen in a population in which vaccine is being used, but not at a high enough level. The eradication of polio can be declared only when the disease has been absent for three years. WHO watches for symptoms of the disease and monitors sewage water—if the virus exists in a population, this is where it will appear.

Critics have suggested that the eradication of polio may have diverted resources from combatting other, deadlier diseases, in particular malaria, which kills many more people across the developing world. Yet polio lives only in humans; malaria can live in other animals, and tetanus even in the ground. Their eradication will be far more challenging.

The eradication of polio would not only alleviate a huge amount of human suffering. It would save the world’s health systems and agencies an estimated $40-50bn a year in treatment costs in the coming two decades. Eradication is nearly complete—but nearly will not do. Getting from 34 cases per year to zero will be the hardest step.