As the outbreak in Syria of a strain of polio from Pakistan demonstrates, when it comes to infectious diseases, human beings are often their own worst enemies.
When Abu Dhabi hosted the Global Vaccine Summit in April, polio’s days finally seemed to be numbered.
Responding to the call from Unicef to see the disease wiped from the face of planet in just six more years, nations including the UAE joined forces with the World Health Organisation (WHO), Unicef and billionaire philanthropist Bill Gates to pledge almost every cent of the estimated US$5.5 billion (Dh20bn) cost of eradicating polio by 2018.
“Ending polio will not only be a historic feat for humanity, but also a huge part of our efforts to reach every hard-to-reach child with a range of life-saving vaccines,” Unicef’s executive director, Anthony Lake, said at the summit.
“Based on what has happened here today, the financing will not be the thing that stands in the way of us achieving polio eradication.”
He was right. As the outbreak in Syria of a strain of polio from Pakistan demonstrates, when it comes to infectious diseases, human beings are often their own worst enemies.
The polio virus, which spreads orally through contact with infected human waste, is thought to have been around as long as we have, but it was not until the late 19th and early 20th centuries that it really started to make itself felt.
Ironically, a disease that had lain dormant and largely ineffective for millennia came into its own as sanitation in the big cities of the West improved. Previously, children exposed to poorly managed human effluent had developed natural immunity to the virus.
With the development of sewers and clean water supplies in the late 19th century, in a few generations polio found vulnerable hosts living cheek by jowl in overcrowded communities – the perfect conditions for the spread of communicable disease.
Isolated clusters of polio began cropping up in European and US cities at about the start of the 20th century, and soon large epidemics were sweeping across both continents. In one of the worst outbreaks, in 1952, more than 57,000 Americans were infected, leaving 3,000 dead and more than 20,000 with varying degrees of paralysis.
For several generations, polio was an ever-present reality in the industrialised West, as witnessed by the list of famous survivors of the disease, including the actors Alan Alda and Donald Sutherland, the singers Joni Mitchell and Neil Young and, most famously of all, Franklin D Roosevelt, the 32nd president of the United States.
Thanks to the introduction of mass vaccinations in the mid-1950s, in the West polio’s expansion was short and, by the close of the 1960s, virtually over.
For the rest of the world, it took a little longer, but on May 13, 1988, the WHO passed a resolution committing its member states to the global eradication of polio by 2000. This mission, the resolution noted, was “a fitting challenge to be undertaken ... on the organisation’s 40th anniversary, and an appropriate gift, together with the eradication of smallpox, from the 20th to the 21st century”.
But the gift would not be delivered on time. The deadline set for the Global Polio Eradication Initiative proved over-ambitious – polio would turn out to be a tougher adversary than smallpox, which claimed its last victim in 1975 and was declared eradicated in 1980.
Without doubt, tremendous progress has been made in the war on polio. In 1988 there were 350,000 cases worldwide, with the disease endemic in 125 countries, including those in much of Europe and all of Africa, the Middle East and Asia.
Although the 2000 eradication deadline passed without victory, by last year the virus was to be found in just five countries, with a record low of only 223 cases, down from 650 the previous year.
But, as a report in October by the Independent Monitoring Board of the Global Polio Eradication Initiative declared, progress this year has been “far less positive”, leaving the revised goal of eradicating polio completely by next year “at serious risk”.
The report was an unabashed exercise in naming and shaming those few countries whose failure to eradicate polio was continuing to threaten the whole world – including Pakistan, where the strain of the virus now found in Syria originated.
It made clear that in Pakistan the vaccination programme, which had reached only 41 per cent of the target population, had been “beaten back by high levels of insecurity that have had a huge effect on accessibility. The loss of life of dedicated public health workers is a source of great sorrow”.
Since the beginning of this year, at least 17 polio workers have been killed in north Pakistan by the Taliban, and the campaign is continuing. Only last month the organisation claimed responsibility for a bomb aimed at police protecting an immunisation team in Peshawar, which killed two people and injured 20.
“Jews and the United States,” said Ahmed Marwat, spokesman for the faction of the Taliban responsible, “want to stamp out Islamic beliefs through these vaccine drops”.
The US bears some responsibility for having imbued such claims with some credibility. Despite the obvious stupidity of killing health workers who have come to save the lives of your own children, the terrorists can source some justification for their belief from the fact that in 2011, the CIA mounted a fake hepatitis vaccination campaign as part of its hunt for Osama bin Laden in Pakistan – a plot that was leaked to the media in July 2011.
This May, Scientific American magazine condemned an operation that it said could have set back polio eradication by 20 years.
“Few mourn the man responsible for the slaughter of many thousands of innocent people worldwide over the years,” it said. “But the operation that led to his death may yet kill hundreds of thousands more.”
Polio is a sufficiently tough opponent on its own without its spread being aided and abetted by self-serving human intervention, as a British epidemiologist, Nicholas Grassly, knows all too well.
Prof Grassly, who heads the vaccine research group within the department of infectious disease epidemiology at Imperial College London, is in India, working with colleagues there trying to understand why the polio vaccine is less effective among poorer communities.
“Our hypothesis is that it reflects what’s in the gut of these kids,” he says. “They have a very high prevalence of gut pathogens which alters the immune function of the gut, so the vaccine is unable to replicate and induce an immune response.”
That phenomenon, he says, is one explanation for the difficulty in eradicating polio. In India, where there have been no cases since 2011, “it certainly made it difficult to eradicate, particularly in the north”.
“It meant that lots of doses had to be given to get to the level of protection that could have been achieved with many fewer doses in a high-income setting,” he says.
Such immunological fine tuning, however, cannot easily be applied in a country where health workers are being regularly attacked and almost 60 per cent of the population has yet to receive even basic vaccine doses.
The reversal of progress in Pakistan is especially galling because last year had been such a good year, during which “progress soared”, according to the Independent Monitoring Board.
The proportion of national campaigns achieving the necessary coverage had doubled to 80 per cent in 12 months and the number of cases dropped from 198 in 2011 to just 58.
That all came to an end in December last year, when the polio programme started to come under attack, “an unprecedented and immensely sad phenomenon”, most evident in Karachi and Khyber Pakhtunkhwa – and now, apparently, with unforeseen circumstances in faraway Syria and beyond.
That the strain of polio in Syria came from Pakistan is not in doubt, says Prof Grassly.
For several years the DNA of all known strains of polio has been sequenced and, because polio evolves rapidly, its mutations leave a trail of genetic “breadcrumbs”.
“By counting those mutations and comparing sequences you get quite a fine resolution on where a virus has come from and how long it’s been since it emerged from a given location,” he said.
The WHO confirmed on Monday that the strain of polio that has so far crippled 13 children in Syria had made its way to the country via Egypt, where it had been found in December last year, with speculation it may have come from Pakistani Islamists passing through Egypt on their way to Syria.
Other samples had also been detected in Israel and the Palestinian territories since February this year, but no cases of polio had emerged in any of these countries because of strong immunisation programmes.
Syria, its health systems disrupted by civil war, was not so lucky.
The outbreak in Syria has necessitated an enormous response across the Middle East, with seven other countries where polio is no longer endemic embarking on expensive campaigns to immunise 22 million children and the members of the WHO’s eastern mediterranean region calling on Pakistan to get its house in order.
And Syrian children are not the only victims of an ideological battle being fought in the badlands of Pakistan’s federally administered rribal areas. Afghanistan, says the Independent Monitoring Board, “would have been free of polio since November 2012, except that it is repeatedly infected with Pakistan polio virus”.
Those two countries, of course, share a porous border. The WHO says that exactly how the virus found its way from Pakistan to Syria remains unclear.
But if, as some suspect, polio came with the Islamist fighters from Pakistan who have joined the rebels trying to depose the president, Bashar Al Assad, then the Taliban, so busy preventing immunisation back home, might be said to have scored something of a deadly goal.