The announcement came out of the blue: after 40 years without a case, poliovirus had returned to the UK.
In a statement released last summer, health officials said a vaccine-derived version of the virus had been detected in London wastewater and was potentially spreading among unprotected families in the northeast of the capital. Similar outbreaks were reported in Jerusalem and New York.
This specific form of the infection, known as vaccine-derived polio virus (VDPV), raised concerns that polio – all but eradicated in the West – was making a resurgence after the pandemic.
VDPV is a rare form of the disease but can cause the same symptoms of traditional polio, including paralysis.
It occurs when children who receive the oral polio vaccine (OPV), which contains a weakened but active virus strain, shed traces of the virus in their stool. This viral residue can then spread among under-vaccinated communities with poor hygiene.
In London, the hypothesis was that a person returning to the UK after receiving the OPV brought the virus into the capital and then passed it onto others who weren’t immunised.
While the risk of an outbreak was considered low, as most of the population in the UK is vaccinated against polio from early childhood, it highlighted the importance of vaccination and the need to maintain high levels of immunity globally.
The detection of VDPV in London demonstrated the ability of the virus to exploit the smallest of cracks in a nation’s defences and rear its ugly head. Until it is completely eradicated, all populations remain vulnerable.
“As long as the polio virus circulates anywhere, then there’s a global risk,” said Nick Grassly, professor of infectious disease and vaccine epidemiology at Imperial College, London. “That is why the spread of polio virus is categorised as of international concern.”
Five years of epidemics
The threat of vaccine-derived polio stems from four sub-regions across the world – northern Yemen, central Somalia, north-western Nigeria and eastern Democratic Republic of Congo (DRC).
All the regions are affected by acute humanitarian challenges, conflict, lack of access and a high-density population with a towering percentage of zero-dose children.
However, DRC is of “particular concern,” says Aidan O’Leary, director of polio eradication at the World Health Organization.
The country has experienced 15 VDPV epidemics in the last five years. In 2022, DRC registered nearly 500 cases of VDPV, which accounted for almost 60 per cent of all cases worldwide, according to data from the Global Polio Eradication Initiative (GPEI). This year it recorded 10 cases, accounting for more than 40 per cent of all VDPV cases worldwide.
Olivier Bakweto was struck down by polio at the age of two, leaving him paralysed from the waist down.
Instead of seeking medical care to help him regain some mobility, his parents opted to consult with a traditional Congolese healer who – as treatment – burnt his feet every day for a year to stimulate them.
Although the majority of those who get polio only experience mild flu-like symptoms, for unlucky individuals like Bakweto, the virus can ravage their nervous system, resulting in life-altering paralysis or even death.
Now, five decades later, the consequences of his parents' decision to forego vaccination still haunt him.
Bakweto lives alongside his wife Zuzi and their six children in a shantytown in Kinshasa, the capital of DRC. Despite earning a university degree, he has been thwarted in his attempts to find employment that can accommodate him as a wheelchair user.
“We fell victims to polio because the vaccines weren’t available like they are now,” says Bakweto. “But now the world has these vaccines, and they should reach all children as soon as they’re born.”
However, conflict in eastern DRC between military forces and the M23 rebel group, together with the vast logistical effort needed to organise vaccination campaigns in a country the size of Western Europe, has made it difficult to roll out jabs.
“A big challenge comes from our lack of access to the eastern regions, which are affected by conflict with the rebels,” says Aimé Cikomola, the director of the government’s programme on vaccination.
Almost 6 million people are displaced because of the conflict, most living in improper conditions which make polio outbreaks more likely.
Veronique Kilumba Nkulu, the country’s deputy minister of health, told the Telegraph that DRC is also threatened by the detection of wild polio in neighbouring countries.
Wild polio was officially declared eradicated in Africa in 2020, but a limited number of cases are starting to cast doubt over the certification. Last year, both Malawi and Mozambique detected their first cases of wild polio in more than 30 years.
“There’s migration between our countries and there’s always a possibility of [Congo] being contaminated again if immunisation coverage is not complete,” said the minister.
The UN, which hoped that 2021 would be a year of recovery, warned last summer that the world was experiencing the largest sustained decline in childhood vaccination programmes in the last 30 years. Compared to 2019, there has been a concerning increase of 6.7 million children who have missed the crucial third dose of the polio vaccine.
In an attempt to combat the spread of VDPV, the oral polio vaccine which has proved so problematic has been improved and updated over the years. But this hasn’t always delivered the desired results, with each new jab kickstarting a new chain of outbreaks.
At least 90 per cent of children should be fully vaccinated to prevent VDPV from spreading among the communities once an OPV campaign starts, experts say.
But in the east of DRC, immunisation currently stands at an estimated 30 percent or below, according to Mr O’Leary.
“It's not a question of which vaccine we use per se,” he adds, “the question is, are we actually getting the oral vaccine into the mouths of the children who are not immunised or under immunised?”
Detection is the foremost important thing in the fight against eradication, but DRC only has one testing lab, called the National Institute for Biomedical Research (INRB).
Testing used to take anywhere from six weeks to several months, which created huge delays in responding to polio outbreaks.
But in a collaboration between Imperial College and INRB, Prof Grassly trained the doctors in DRC on how to use a viral genome sequencing technique which can decrease the testing to three days.
After the outbreak is confirmed by the lab, an outbreak response is devised by the country’s Polio Emergency Operations Committee (COUP).
Its interim chief, Colonel Dr. Anicet Mwehu, leads the committee’s efforts to plan the emergency response in coordination with the government and international partners like GPEI and UN agencies.
“We are in a critical phase and without the help we receive from partners we wouldn’t be able to address these outbreaks,” said Mwehu.
The plan culminates with the deployment of vaccinators to the affected areas.
In line with objectives set by the DRC government, frontline health workers aim to start vaccinating 14 days after an outbreak is declared, but with delays in testing and a lack of funds, it can take the COUP more than three months until the first vaccines are delivered.
“By the time you’re responding you don’t know if the virus is still there or if it has moved somewhere else,” says Prof Grassly.
The remote areas in which many communities live are also a challenge. The Telegraph joined vaccinators on a 34-mile boat ride to the Lukunga Islands on the Congo River.
Before April last year, the farming community on the islands had no permanent health centre, no roads and no electricity. Vaccinators need to use boats to reach its people, but often they don’t have enough money for petrol, so they use pirogues, local wooden boats which require passengers to paddle.
During Covid lockdowns, the island’s inhabitants were completely isolated. Parents of new-born children had to travel to Kinshasa to give their children the routine immunisation, requiring costs which can stack up for the locals.
With only Afghanistan and Pakistan affected by wild polio, and only four sub regions in the world affected by VDPV, the eradication of polio remains tantalisingly close.
But for people like Bakweto and others like him, it is too late.
He shares the squalid living conditions in the slum with other polio survivors. His neighbour, Frederick Kasanga, relies on a bicycle to navigate his surroundings, and Rose Ndombe, an employee of the Ministry of Interior, must crawl up a flight of stairs every day to reach her first-floor office.
As Bakweto and his neighbours know all too well, the plight of polio is compounded by their social isolation and economic struggles, leading to a lifetime of poverty, pain, and disability. But despite having little to his name, Bakweto and his wife Zuzi are happy.
“I am happy even though I’m disabled,” he says. “I would have never believed if you said I would have a loving wife and so many healthy children.”
