The folly of declaring Africa polio-free

In late August, the independent Africa Regional Certification Commission for Polio Eradication announced  the elimination of wild poliovirus on the African continent. The last wild cases of the disease, which can cause debilitating paralysis and death, were found in the state of Borno in northeast Nigeria during the summer of 2016. Following a difficult few years in which the Global Polio Eradication Initiative suffered from a surge of cases in Pakistan and Afghanistan and the worldwide spread of cases associated with mutations of the polio vaccine, eliminating wild polio in Africa would be a stunning achievement and significant milestone. It now appears to be a done deal.
But an aerial view of Borno hints at why the story may not be so simple. Outside the walls of Maiduguri, the state's capital city, lie a rugged and highly contested terrain that's mostly inaccessible to health workers. Humanitarian hubs with camps for displaced citizens are largely accessible only by helicopter. In 2019, I worked with an international organization, REACH, to obtain data on the needs of people from these inaccessible areas in support of humanitarian response efforts. What I saw there contradicts the conclusions of the World Health Organization (WHO) and the Global Polio Eradication Initiative.
I believe that given the extreme inaccessibility caused by conflict, low vaccination rates, and logistical constraints that limit disease surveillance in many parts of rural Africa - a situation only made worse by Covid-19 - the declaration that wild poliovirus has been eliminated from the continent is premature.
The rush to declare victory reflects the chasm between high-level rhetoric and the day-to-day reality of life in Nigeria.
The eradication anouncement comes after a four-year period in which the African continent has not recorded a case of wild polio. (A minimum of three consecutive years case-free is required to begin the certification process.) The Africa Regional Certification Commission granted its approval after reviewing documentation that Nigeria had met specific criteria indicating strong surveillance, such as detecting at least three non-polio cases of paralysis per 100,000 children under age 15 and testing the stool samples of at least 80 per cent of paralysed children.
But eradication programmes inherently operate on the fringes of detection capacity, and northeast Nigeria poses unique challenges. The Boko Haram insurgency, now more than a decade old, looms ever-present beyond towns like Maiduguri. Rural residents of contested areas face abduction, arbitrary killings, severe food insecurity, and routine arson of schools, health facilities, and shelters. Despite the surge of attention following the mass kidnapping in 2014 of schoolgirls in Chibok, child abductions remain commonplace.
The dangers are especially pronounced in Central Borno and the Sambisa Forest, where a faction of Boko Haram known as JAS has held large populations captive, destroyed health centres, and created a parallel health system that is unconnected to the polio surveillance network. Children in JAS territory are less likely to be vaccinated, and any polio cases in this part of Borno are more likely to go undetected.
Though countries are eligible for eradication certification after going three years without detecting a case, there is nothing magical about this timeline. It was derived from the smallpox eradication programme, where three years represented three times the longest period between reported cases in a country - eight months - with an additional buffer year. The epidemiology of polio, which only causes paralysis in about one of every 200 cases, calls for a longer timeframe. And beyond epidemiological differences, a three-year certification period should not apply where populations have been held entirely captive for four or five years.
Despite these red flags, declarations of success have continued, ensuring that any future wild polio cases in Nigeria - or elsewhere in Africa - will be framed as a setback at best, or hidden at worst. A four-year absence of reported polio cases from Borno is insufficient evidence that wild poliovirus has been eliminated in Africa. Ignoring this reality may prove a shortsighted misstep for polio eradication: Any complacency in prevention efforts could allow the disease to come roaring back out of hiding. Senior leaders in the effort should not be so easily tempted by the lure of prematurely declaring victory.
Jordan Schermerhorn is a researcher working on infectious diseases in fragile states and conflict settings throughout sub-Saharan Africa. -undark.org