The World Health Organization and British health officials said on Wednesday that a kind of poliovirus originating from immunizations had been found in samples of the sewage from London, adding that more testing was being done.
In Britain, where the devastating illness was completely eradicated two decades ago, no human instances of polio have been discovered.
In a statement, the WHO reported that environmental samples from the British capital contained "type 2 vaccine-derived poliovirus (VDPV2)."
"It is important to note that the virus has been isolated from environmental samples only," it said, stressing that "no associated cases of paralysis have been detected."
However, it stated that "any form of poliovirus anywhere is a threat to children everywhere."
Polio is a severe and possibly deadly viral illness that primarily affects children under the age of five. In recent decades, a vast worldwide effort has come close to eliminating polio.
Since 1988, when polio was prevalent in 125 countries and 350,000 cases were reported globally, cases have dropped by 99 percent.
Only Afghanistan and Pakistan currently harbor the wild form of the virus, while other countries occasionally see outbreaks due to a particular vaccination that contains minute quantities of weak but live poliovirus.
Check vaccination histories
The oral polio vaccine (OPV), which multiplies in the stomach and can spread to others through fecal-contaminated water, won't harm the child who had the vaccination but may infect their neighbors in areas with poor sanitation and immunization rates.
This type can cause significant sickness and paralysis in persons who have not had the polio vaccine, although being less potent than the wild poliovirus.
In 2020, the WHO reported 959 confirmed cases of VDPV2 worldwide.
The discovery in the London sewage samples, according to polio eradication specialist Kathlene O'Reilly, shows "there may be localized spread of poliovirus, most likely within individuals that are not up to date with polio immunizations".
"The most effective way to prevent further spread is to check vaccination histories, especially of young children, to check that polio vaccination is included," she added.
According to the WHO, London has a roughly 87 percent vaccination rate against polio.
The UN's health agency has demanded that inactivated polio vaccine be used as a replacement for OPV worldwide (IPV).
British health officials stated that it was probable that the virus discovered in the sewage samples had been acquired by someone who had recently had OPV vaccination overseas after Britain ceased using it in 2004.
We are not isolated
Parents occasionally ask why immunizations are being administered for illnesses like polio, which have been eradicated in the UK, according to David Elliman, a consultant pediatrician at Great Ormond Street Hospital.
"The answer is that, although we are an island, we are not isolated from the rest of the world, which means diseases could be brought in from abroad," he explained.
"The finding of vaccine-derived polio virus in sewage proves the point."
The virus isolates were discovered, according to the UK Health Security Agency (UKHSA), in "multiple sewage samples collected from the London Beckton Sewage Treatment Works between February and June 2022."
Around four million people live in the area of north and east London where the facility is located.
According to health officials, a few poliovirus isolates are often found in sewage samples from the UK each year, but they are typically unrelated. However, in this instance, the isolates were "genetically related," which is unusual.
"This has prompted the need to investigate the extent of transmission of this virus in northeast London," UKHSA stated.
Reviewed by Lilit
on
June 28, 2022
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