The paralysis-causing disease was officially eradicated in the UK in 2003 and the last domestic outbreak was in the 1980s. But dwindling vaccination rates, in part due to complacency, appear to have allowed polio to creep back in decades later.
The archaic disease has existed as long as human civilisation itself, with the earliest records dating back to ancient Egypt.
But it was until the 1800s that outbreaks began to really take off.
Millions of Brits will remember the devastation polio caused in the early 1950s and why it was one of the most feared infections in the world. The UK was rocked by a series of polio epidemics in the mid-20th century that saw thousands crippled by the virus each year.
Mary Berry, the ex-Great British Bake Off judge, was hospitalised after contracting polio aged 13, leaving her with a twisted spine and damaged left hand.
Despite being eradicated in most of the world, it still spreads in two countries — Afghanistan and Pakistan — while parts of Africa suffer flare-ups of vaccine-derived versions of the virus.
Here, MailOnline takes a look at the history of the virus:
Polio epidemics, when the virus is constantly spreading within a community, did not start happening until the late 1800s.
But records suggest it dates back to as early as 1570 BC in ancient Egypt.
This is based on a drawing on a stele — a stone slab — which shows a priest with a withered leg and using a cane to help him walk.
And an Egyptian ruler called Siptah, who died in 1188 BC, is thought to have had polio based on his deformed left leg and foot, spotted by archaeologists who found his mummy in 1905.
But apart from these two incidents, polio largely vanished from the record books until it was logged in in 1789 by London-based Dr Michael Underwood.
He published the first clear description of polio in infants, who are particularly vulnerable to the disease, in a medical textbook, calling it ‘debility of the lower extremities’.
Records show polio dates back to as early as 1570 BC in ancient Egypt. This is based on a drawing on a stele – a stone slab (pictured) – which shows a priest with a withered leg and using a cane to help him walk
In the early 1800s, a handful of polio cases were sporadically reported in medical journals.
But scientists believe people were commonly exposed to the virus in the typical unhygienic environments of the time, especially when they were young.
However, polioviruses started causing problems in Europe and North America at the end of the 1800s. This was, bizarrely, blamed on sanitation improving.
Polio spreads through consuming an infected person’s faecal matter — which can happen as a result of poor hand hygiene.
While better water and sewage systems saw the demise of typhoid and cholera, outbreaks of polio became more common.
Three-quarter of those who become infected don’t have symptoms. But around a quarter suffer a flu-like illness, including a sore throat, fever and tiredness.
Up to one in 200 will develop more serious symptoms that affect their brain and spinal cord, including paralysis.
Professor Ian Jones, a virologist at Reading University, explained the virus ‘wasn’t a problem until hygiene improved’.
Previously, low levels of infection would have given immunity to people but the unforeseen circumstance of better living conditions was that this declined and polio ‘took off’, he said.
Professor Paul Hunter, an infectious disease expert at the University of East Anglia, told MailOnline that although polio has been around for centuries or millennia, it was only during the early part of the 20th century that big epidemics of paralytic polio took off.
He explained: ‘When every child got infected with poliovirus in the first couple of years of life you still saw some paralysis but it was only when infections were delayed until older age that such paralysis became more common.
‘Young children who contract poliovirus infection generally suffer only mild symptoms, but delay those infections to teens and adulthood and paralysis becomes more common.’
The first epidemic struck more than a dozen people in Norway in 1868, while the second, which occurred 13 years later, caused a similar number of confirmed cases in Sweden. An outbreak in the US in 1894 saw 132 people infected.
It was in 1916 that the first large-scale epidemic took hold in Brooklyn, New York, with more than 9,000 cases and 2,000 deaths.
The outbreak spread to the rest of the US and led to more than 27,000 cases and 6,000 polio deaths that year.
Newspapers published the names and addresses of infected people, ‘keep out’ notices were nailed to their doors and their families were quarantined.
Parents were urged to keep their children away from public spaces, such as swimming pools, parks and beaches, over virus fears.
The outbreak triggered concern across the world and sped up research into the illness.
Scientists had already made some progress in understanding and treating the virus.
In 1840, German orthopaedic Dr Jacob von Heine had become the first to produce a robust study on polio. He suggested that the disease may be contagious.
By 1908, Austrian physicians Karl Landsteiner and Erwin Popper said that polio may be caused by a virus.
Early treatments of the disease included tying the paralysed limbs of infected patients to splints, in a bid to stop their muscles from tightening.
But by 1928, an invention called the iron lung was rolled out to revolutionise how the disease was treated. The contraption – a respirator that resembled a ‘coffin on legs’ – was developed for patients whose lungs were so paralysed that they could no longer breathe unaided. Paul Alexander, 76, from Texas, is still in the machine today — 70 years after contracting polio at the age of six in 1952
But by 1928, an invention called the iron lung was rolled out to revolutionise how the disease was treated.
The contraption – a respirator that resembled a ‘coffin on legs’ – was developed for patients whose lungs were so paralysed that they could no longer breathe unaided.
It was first used that decade to save an American child infected with the virus who needed help breathing. The majority patients stayed inside the chamber for short spells until their lungs recovered.
But some struck down by permanent paralysis stayed inside the machines for the rest of their lives.
Paul Alexander, 76, from Texas, is still in the machine today — 70 years after getting polio at the age of six in 1952.
And by 1930, Elizabeth Kenny, a self-trained nurse from Queensland, Australia, developed a treatment applying hot packs to muscles and exercise to keep stimulating nerve cells and avoid long-term muscle damage. The methods are still used today.
As part of the increased focus on research, Australian virologists Sir Macfarlane Burnet and Dame Jean MacNamara identified for the first time that there were three types of the polio virus in 1931.
The fight against the virus was further boosted when a team of scientists at Harvard Medical School, led by Dr Jonas Salk, in the 1940s used blood samples of infected patients to extract and grow the virus in live cells.
By 1955 the team, with the support of funds from the March of Dimes non-profit organisation, developed the first effective vaccine — an injectable inactive (killed) polio vaccine (IPV).
Nearly 2million children in the US were jabbed as part of the largest medical trials ever seen at the time.
They proved successful and 450million doses of the jab were dished out across the country. Cases subsequently fell from 18 per 100,000 people to two per 100,000.
The following decade, a team at the University of Cincinnati in Ohio, led by medical researcher Dr Albert Sabin, developed a second vaccine using a live version of the virus that could be given in drops through the mouth.
This vaccine was much more effective and became the most popular throughout the world.
Politicians in the US didn’t support Dr Sabin’s oral poliovirus vaccine (OPV), so he tested it in the former Soviet Union.
The USSR rolled out the jab and polio subsequently declined. Drops in cases were also seen in nearby Eastern Europe and Japan.
The US licensed the jabbed in 1961 and it became the main vaccine used worldwide.
The fight against polio was further boosted when a team of scientists at Harvard Medical School, led by Dr Jonas Salk, in the 1940s used blood samples of infected patients to extract and grow the virus in live cells. Pictured: Dr Salk at the Municipal Hospital laboratory in April 1955 after announcement of the successful vaccine results
Great Britain was pronounced clear of polio in 2003 with the last case coming in 1984. A young girl is pictured getting her polio jab in May 1956
By 1955 researchers at Harvard Medical School, with the support of funds from the March of Dimes non-profit organisation, developed the first effective vaccine against polio — an injectable inactive (killed) polio vaccine (IPV). Pictured: children getting a lump of sugar while getting a polio vaccine at a mobile unit in Blackburn in Lancashire, England in 1965
Professor Jonathan Ball, a virologist from the University of Nottingham, told MailOnline that polio had a ‘devastating effect’ worldwide and the introduction of the two jabs was ‘immense’.
Studies throughout the 1970s and 1980s revealed the virus was widespread in many richer nations, which pushed leaders to introduce routine vaccination using the OPV in national immunisations programmes.
The jabs saw polio vanish in developed countries. In the UK, cases fell from a peak of 8,000 a year to just a few hundred before being eradicated.
In the US, infections dropped from a peak of 58,000 to zero just a few years after the jab was dished out.
Kathleen O’Reilly, an associate professor in statistics for infectious disease and expert in polio eradication, told MailOnline: ‘After the second world war cases of paralytic polio in England and Wales rose considerably, reaching several thousand cases each year.
‘Vaccines were developed in response to these worrying outbreaks, and were introduced in the late 1950s.
‘The number of polio cases quickly declined, and since the 1970s only a small number of cases were reported each year. There has not been a single case of polio in the UK since 1984.’
But in poorer nations, where the virus caused fewer outbreaks, uptake was much lower.
The World Health Organization (WHO) launched an worldwide immunisation rollout in 1974, in an attempt to vaccinate all children against polio.
By 1988, the UN health agency set the target of eradicating the virus globally by 2000. Two years later, a global virus surveillance system is set up to detect the virus.
The US logged its last case in 1991, in a three-year-old boy called Luis Fermin Tenorio living in Junin, northern Peru.
The WHO certified the region as polio-free three years later — the duration set by the agency before a nation can be deemed to have eradicated the virus.
A team at the University of Cincinnati in Ohio, led by medical researcher Dr Albert Sabin, developed a second vaccine using a live version of the virus that could be given in drops through the mouth. This vaccine was much more effective than the inactivated one, and became the most popular throughout the world. Pictured: a health worker giving a oral polio vaccine to a child in Karachi, Pakistan
There was also success in ridding the world of two wild types of the virus, with type two eradicated in 2015 and type three stamped out by 2019. However, the WHO global goal of eradicating the virus by 2000 has still not been met. Polio is endemic in Afghanistan and Pakistan. Pictured: a child in Kabul, Afghanistan being given the oral vaccine in November 2021
Nearly every country in the world used the oral polio vaccine in their rollout. But after infections were brought under control in the US and the UK, both countries stopped using this vaccine — in 2000 and 2004, respectively. Other nations followed suit.
While the oral version provides higher levels of protection against infection — meaning it is more effective at limiting spread in endemic countries — the weakened live virus in the vaccine can mutate on very rare occasions and cause paralysis.
It can also spread to others and cause an outbreak of vaccine-derived polio.
Professor Hunter explained that the live vaccine does a better job at stopping infection ‘but can very rarely cause paralysis’.
Meanwhile, the inactivated vaccine ‘doesn’t cause infection and is still excellent at stopping paralysis but not quite as good at preventing infection’, he said.
Only a handful still use the oral vaccine.
In 2002, Europe was certified as polio-free. Its final case was logged in a 33-month-old child in Turkey in 1999.
The Western Pacific was labelled polio-free in 2000, with the last confirmed infection being in a 15-month-old girl called Mum Chanty in Phnom Penh, Cambodia. And the WHO confirmed South East Asia is virus free in 2014.
There was also success in ridding the world of two wild types of the virus, with type two eradicated in 2015 and type three stamped out by 2019.
However, the WHO global goal of eradicating the virus by 2000 has still not been met. Polio is endemic in Afghanistan and Pakistan.
Travellers from these two nations frequently spread the virus to other countries.
China lost its polio-free status in 2011 after the infection spread to the country from Pakistan. However, it regained it after the outbreak fizzled out.
Professor Ball explained: ‘The live vaccine has proven to be incredibly effective at eliminating the virus.
‘But on rare occasions it can revert to wild-type and cause the disease; that’s why countries that do get rid of the virus switch to using killed vaccine to keep their populations safe.’
Professor Jones said the dilemma around polio is now around eradication. ‘Is it worth the cost in terms of money and lives lost to eradicate the last few cases or is it better to maintain where we are?
‘Lastly, another dilemma, if it is eradicated how long do you continue to vaccinate and with what?’
UK health chiefs revealed polio could be spreading in the community for the first time in four decades after the virus was spotted in sewage samples in parts of London on June 22, 2022. It is a vaccine-derived strain.
The virus was detected at the Beckton sewage treatment works, which covers a population of four million in north and east London
But there are signs it is spreading between people as officials have picked up several samples from different people, each with new mutations.
Professor Hunter added: ‘Whilst most of the world has moved away from live attenuated vaccine some countries still use it and there is a risk that you can get secondary infections (generally a family member) which very rarely can be associated with paralysis in someone who has not been immunised.
‘The concern here is that even a vaccine derived virus if it continues to spread could eventually recover its full virulence over a year or two and then cause an outbreak of paralytic polio in people who have not been vaccinated and that would be a disaster.
‘So probably the current situation does not pose an immediate threat to public health but if transmission goes on long enough and the virus recovers its virulence it could become a public health disaster.’