A Clear-Eyed Look at Polio
Over the past 25 years, international eradication efforts have wiped out 99 percent of the cases of the deadly virus. So why is the last 1 percent now all of the story?
Things have been going really well for polio eradication — in fact, so well that the world hit an all-time low in 2012: Cases were down more than 99 percent since 1988. Still, it seems like the bad news about polio outbreaks and the difficulties in providing vaccines dominates the headlines. On May 5, the World Health Organization declared an international health emergency to further contain the virus — targeting Pakistan, Syria, and Cameroon as countries where the virus has spread.
But the thing is, fighting polio has never been easy.
Over the past 25 years, a global effort to eradicate polio has immunized more than 2.5 billion children, and cases worldwide declined from 350,000 cases in 1988 to just over 400 in 2013. This success was driven by the Global Polio Eradication Initiative and governments around the world that have, since 1988, supported the goal of reaching all the world’s children — no matter where they live — with the polio vaccine. The Bill & Melinda Gates Foundation, where I lead the global development team, has been a major funder of this initiative since 2009.
However, despite this incredible achievement, the obstacles faced on the last mile to success have now seemingly become 100 percent of the whole polio story.
By early 2011, polio was only coming from three countries where transmission of the disease had never been stopped: Afghanistan, Pakistan, and Nigeria. By the end of 2012, the world had the lowest number of polio cases ever. Governments and donors around the world stepped up to support a new eradication plan, pledging $4 billion over six years and cheering the goal of a polio-free world by the end of 2018. So, in 2013, when India was well on its way to officially eliminating polio, with no new cases since January 2011, optimism was high and momentum was strong.
But the ticker-tape parade wasn’t scheduled just yet. Beginning in December 2012, a new and alarming set of challenges emerged: deplorable acts of violence against health workers delivering the polio vaccine, a Taliban-imposed ban on polio vaccination campaigns in Pakistan’s Waziristan region, and escalating violence by Boko Haram in northeast Nigeria.
Since then, more than 50 polio vaccinators and security personnel in Pakistan and northern Nigeria have been murdered; in Pakistan, 400,000 children living in North and South Waziristan and the Federally Administered Tribal Areas have been denied access to the polio vaccine. Pakistan has seen the erosion of two years of dramatic progress against polio, and the resulting spike in cases has led to the introduction of wild poliovirus in Syria, Iraq, and other countries in the Middle East. Adding to the challenges was an outbreak of 200 polio cases in previously polio-free countries in the Horn of Africa and a separate spread of the disease to Cameroon and Equatorial Guinea.
Altogether, these tragic events amounted to serious challenges — but they weren’t a defeat. Over the past few months, the media has managed to ignore the other part of this story: Polio eradication efforts have always been beset by numerous challenges, among them the need to vaccinate millions of children living in conflict zones, geographically remote areas, and communities that lack basic health-care infrastructure. Due to successful efforts to address these challenges on every continent, only two reservoirs of the poliovirus remain today. This means that all wild poliovirus strains that exist in the world today originated either from the border areas between Afghanistan and Pakistan or from northeast Nigeria.
Despite the tragedies in recent months in the final polio reservoirs, local authorities in these last reservoirs are showing renewed determination to ensure greater protection for vaccination workers and to reach more children with vaccines.
Since January of this year, provincial governments, in close coordination with the federal government of Pakistan, have provided hundreds of thousands of children with the polio vaccine coupled with other health services, including lifesaving vaccines, clean water, and soap. These health services were delivered for the first time in and around Peshawar, Pakistan, through the "Justice for Health" program, rolled out by the local government’s ruling party, Pakistan Tehreek-e-Insaf. With thousands of police deployed to protect the vaccination teams, the effort has proceeded without incident. Other provincial governments also working with the federal government have launched similar campaigns in Karachi, and local polio vaccination teams are setting up at key transit points along the border of North and South Waziristan. Global and local Islamic leaders and scholars have issued fatwas to endorse the value of vaccination and to urge parents to protect their children from polio. Under the leadership of the grand imam of the Grand Mosque of Mecca, Islamic scholars recently joined the eradication effort with a pro-polio vaccination "Jeddah Declaration" and six-month action plan to address challenges in the remaining polio-endemic parts of the Islamic world.
The progress has been especially dramatic in Nigeria. In 2012, it was the only polio-endemic country with an increase in cases. Significant progress was made in 2013, and so far this year, only two cases of wild poliovirus have been reported. The latest anti-polio campaigns in northern Nigeria have reached historic rates of vaccination coverage. Vaccinators have gained access to thousands of settlements where children had never before been reached, and vaccination teams are increasingly welcomed as they combine the polio vaccine with other routine childhood immunizations.
Afghanistan has nearly eliminated polio, with four cases reported so far this year. Of the four, only one case is endemic to Afghanistan — the other three cases were the result of the virus originating in and being transmitted from Pakistan.
The confirmation of a polio case in a previously polio-free country is always discouraging, but not unanticipated. In the last year, the response to outbreaks has been far-reaching. In Syria, for example, where the civil conflict has created tremendous humanitarian challenges, response teams are working with local nongovernmental organizations to vaccinate even the hardest-to-reach children, and the number of new polio cases appears to have declined, with no new cases since January of this year. Governments of neighboring countries have also quickly mobilized, and more than 20 million children and adults in Syria and neighboring countries have been vaccinated. In Somalia, vaccination teams are concentrating on locations with highly mobile populations, and new cases have steadily diminished. The Horn of Africa has only seen one case of polio to date in 2014. And, in response to outbreaks in Cameroon and Equatorial Guinea, mass vaccination campaigns and surveillance efforts are under way in those countries and in neighboring Gabon and Congo (Brazzaville).
A month ago, I att
ended a ceremony celebrating India’s success in stopping polio and the polio-free certification of 11 countries in Southeast Asia, home to 1.8 billion people. This achievement cannot be overstated, given that India was long regarded as the hardest place on Earth to end polio due to the country’s population density, high rates of migration, poor sanitation, high birthrates, and low rates of childhood immunization.
At a global level, of the two types of wild poliovirus left in the world, we’ve only seen one type in the past 16 months, signaling the shrinking genetic diversity of a disease that has thrived for millennia.
As the global polio eradication program has proved time and again, the world can overcome new obstacles as they arise. Setbacks are inevitable in the ambitious effort to rid the world of any infectious human disease — a feat that has been achieved only once before, with smallpox. But these challenges should all be viewed in context: In spite of the newest obstacles, a world free of polio is still on the horizon.