The pandemic has ended. For Africa at least. Sort of.
The pandemic in question is not coronavirus, but poliovirus, which causes crippling paralysis in a minority of children. On August 25, the World Health Organization announced that wild poliovirus had been eradicated in Africa following its disappearance in Nigeria.
Distracted by Covid-19, few people noticed. That’s a pity. It brings tantalisingly close the goal of eradicating polio from earth in what would be only the second elimination of a virus that affects humans in history. The other was smallpox, declared eradicated in 1980.
Wild polio now exists only in Afghanistan and Pakistan. A generation ago, it was paralysing 75,000 children a year in Africa alone.
The treadmill struggle against polio holds multiple lessons for a world newly sensitised to the threat of microbes. Among them, the contradictions of development, the key role of public health, the politics of vaccines and the stubbornness of pathogens.
Polio is an ancient disease. Egyptian stele from the 15th century BC depict pharaohs with withered legs. More recent epidemics occurred in Norway in the 1860s. By the 1940s, there were regular outbreaks all over Europe. In 1952 alone, some 21,000 American children were paralysed.
Paradoxically, the virus spread because of better hygiene. As sanitation improved, fewer children were exposed to poliovirus, which is mainly transmitted through the so-called faecal-oral route, usually in water. That left them vulnerable. Swimming pools became places of danger.
Development often has side effects. It brings humans into closer contact with animals and with each other. Progress allows pathogens to hitch rides aboard aeroplanes.
Polio was all but eradicated in rich countries thanks to vaccines. The first, developed in 1953 by Jonas Salk, was a so-called “killed vaccine” administered through injection. By the late 1950s, some 450m doses had been given. In the US, the incidence of paralytic polio fell from 18 per 100,000 to two. The last domestic case was 1979.
In the late 1950s, Albert Sabin came up with a so-called live attenuated vaccine. Given orally, the Sabin vaccine is cheap and easy to administer but, in roughly three cases per million, it can itself cause paralysis. This occurs after it enters the water system where it can mutate and infect children in under-immunised communities.
Three cases per million is tiny compared to the 5,000 cases per million that can result from wild polio infections. From a public health perspective, it is a no-brainer.
The drama of polio eradication has played out in Nigeria, which in 2012 accounted for more than half of worldwide cases. Most were in the north of the country where insecurity made it hard to get to children and where conspiracy theories persuaded some that the vaccine was a western plot.
In 2003, an outbreak in Nigeria’s north quickly spread to 20 countries, a warning for the coronavirus generation. Nigeria again seemed on the verge of elimination in 2016 when four cases suddenly appeared in the north-eastern state of Borno.
The WHO appointed Musa Audu, who had been successfully snuffing out polio elsewhere in Nigeria, to deliver the final blow. When he arrived in Borno, it was in the grip of a Boko Haram fundamentalist insurgency. Swaths of the state were under rebel control and there were daily roadside bombs. Many areas were accessible only by helicopter. Some were not accessible at all.
Nigeria’s president Muhammadu Buhari has not always been the most dynamic leader. But on polio, he swung into action. Not only did he instruct the military to co-operate with health workers, sometimes administering polio vaccine themselves. He also made a show of giving the vaccine to his own grandchild, a display of leadership that encouraged millions of parents to let their children be immunised too.
The last case of wild polio virus in Nigeria was four years ago, but there were 320 cases of “vaccine-derived” polio across Africa last year. These affect under-immunised communities, so further mass campaigns are needed.
Public health is expensive and frustrating. Despite its name, it can be hard to explain to the public. Yet the legacy of such campaigns is lasting. Not only have some 1.8m children in Africa been saved from paralysis in the past 25 years. The labs, surveillance and track-and-trace systems that were built for polio — and Ebola and HIV — have stood the continent in decent stead to tackle coronavirus.
Africa is putting up a strong fight against Covid-19. That is in large part thanks to its public health battles of old.
Source: Financial Times
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