The World Health Organization and British health officials said Wednesday that a type of poliovirus from vaccinations has been found in sewage samples, implying that further research is underway.
In Britain, no human history of polio was found, which had been fully eradicated two decades ago.
In a statement, the WHO claims that "type 2 vaccine-derived poliovirus (VDPV2)" had been discovered in environmental samples in the British capital.
"It''s important to note that the virus has only been isolated from environmental samples," the author said, highlighting that "no associated symptoms of paralysis have been detected."
"Any form of poliovirus anywhere is a concern for children everywhere," says the report.
In recent decades, a massive international effort has come to an end to polio, a serious and potentially fatal viral illness that mainly affects children under the age of five.
Since 1988, polio was endemic in 125 countries, and 350,000 cases were recorded worldwide.
The wild version of the virus now exists only in Afghanistan and Pakistan, but a type of vaccination that contains small amounts of weakening but live polio has still cause some discomfort elsewhere.
Check vaccination histories
The oral polio vaccine (OPV) replicates in the gut and can be passed to other individuals through fecal-contaminated water, which means it won''t hurt the child who has been vaccinated, but it may infect their neighbors in areas where hygiene and immunization levels are low.
Persons who are not vaccinated against the disease are susceptible to serious illness and paralysis, although the variant is still less effective than the wild poliovirus.
According to the WHO, there were 959 confirmed cases of VDPV2.
Kathlene O''Reilly, a policy eradication expert, told Wednesday that the discovery in the sewage samples in London suggest that "there may be a localized spread of poliovirus, most likely within individuals that aren''t up to date with polio immunizations."
"The most effective way to prevent further spread is to check vaccination histories, particularly of young children, to ensure that polio vaccination is included," she said.
The WHO claims that the number of people immunization for Polio in London has been at least 87%.
The United Nations'' health ministry has called for the operation of the OPV to be phased out worldwide and replaced with the inactivated polio vaccine (IPV).
In 2004, Britain had withdrawn from using the OPV, and British health authorities said it was probable that the virus found in sewage samples had been imported by someone who was recently vaccinated with it abroad.
We are not isolated
Parents often wonder why vaccinations continue to be used against diseases that have been eliminated in the United Kingdom, such as polio.
"The answer is that although we are an island, we are not isolated from the rest of the world, which means diseases may be brought in from abroad."
"The discovery of the vaccine-derived polio virus in wastewater proves the point."
The United Kingdom Health Security Agency (UKHSA) claims that virus isolates were discovered in "multiple sewage samples collected from the London Beckton Sewage Treatment Works between February and June 2022."
The plant covers a vast expanse of north and east London, which is home to around four million people.
On average, a couple of poliovirus isolates are detected in UK wastewater samples each year, but they tend to be unrelated, according to health authorities, indicating that the isolates were "genetically related."
"This has prompted the need to look into the extent of transmission of this virus in northeast London," the UKHSA said.