A type of poliovirus has been detected in sewage samples in London, prompting the health authorities in Britain to issue a warning, AFP reported on Wednesday.

The disease was fully eliminated in the country two decades ago and no cases of polio have been found since then. The last case of wild polio was confirmed in 1984 in the United Kingdom. In 2003, the country was declared polio-free.

The UK Health Security Agency said samples from the Beckton Sewage Treatment Works in London tested positive for vaccine-derived poliovirus type 2. “On rare occasions, it can cause serious illness, such as paralysis, in people who are not fully vaccinated,” it said.

The poliovirus was detected during a routine surveillance of the disease, the World Health Organization said.

“The Global Polio Laboratory Network has confirmed the isolation of type 2 vaccine-derived poliovirus, or VDPV2, from environmental samples in London,” the global health body said on Wednesday. “It is important to note that the virus has been isolated from environmental samples only – no associated cases of paralysis have been detected.”

Unrelated polioviruses are detected in sewage samples in the country every year, the UK Health Security Agency said. These are from persons who take oral polio vaccine in another country and travel to the UK. These individuals can “briefly shed traces of the vaccine-like poliovirus in their faeces”, it added.

However, samples detected between February and May had the same origin and were related.

“The detection of a VDPV2 suggests it is likely there has been some spread between closely-linked individuals in North and East London and that they are now shedding the type 2 poliovirus strain in their faeces,” the agency said.

Additional sewage samples from the main wastewater treatment plant were sent for analysis, the World Health Organization said.

The global health body warned that any type of poliovirus anywhere is a “threat to children everywhere”.

The UK Health Security Agency, however, said that vaccine-derived poliovirus is rare and its overall risk to the public is “extremely low”.

“Vaccine-derived poliovirus has the potential to spread, particularly in communities where vaccine uptake is lower,” said Dr Vanessa Saliba, consultant epidemiologist at the agency. “Most of the UK population will be protected from vaccination in childhood, but in some communities with low vaccine coverage, individuals may remain at risk.”

The National Health Service in London said that most residents are fully protected against polio.

“But the NHS will begin reaching out to parents of children aged under five in London who are not up to date with their polio vaccinations to invite them to get protected,” said Jane Clegg, chief nurse at the National Health Service in the city.

Healthcare professionals have been directed to investigate as well as report persons showing any polio-related symptoms.

What the CDC says

According to the Centers for Disease Control and Prevention, the poliovirus is contagious and can infect a person’s spinal cord, resulting in paralysis.


  • Sore throat
  • Fever
  • Tiredness
  • Nausea
  • Headache
  • Stomach pain
  • Paresthesia (feeling of pins and needles in the legs)
  • Meningitis
  • Paralysis