WHAT AND WHERE: THE DISCOVERY IN LONDON
THE UK Health Security Agency said the poliovirus was found in sewage samples collected from the London Beckton Sewage Treatment Works.
A spokesman said: “As part of routine surveillance, it is normal for one to three ‘vaccine-like’ polioviruses to be detected each year in UK sewage samples but these have always been one-off.
“These previous detections occurred when an individual vaccinated overseas with the live oral polio vaccine (OPV) returned or travelled to the UK and briefly shed traces of the vaccine-like poliovirus in their faeces.
“Investigations are under way after several closely-related viruses were found in sewage samples taken between February and May.
“The virus has continued to evolve and is now classified as a vaccine-derived poliovirus type 2 (VDPV2), which on rare occasions can cause serious illness, such as paralysis, in people who are not fully vaccinated.
“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 virus has only been detected in sewage samples and no associated cases of paralysis have been reported – but investigations will aim to establish if any community transmission is occurring.”
Dr Vanessa Saliba, consultant epidemiologist at UKHSA, said: “Vaccine-derived poliovirus is rare and the risk to the public overall is extremely low.”
However, she said people should make sure they and their children are fully vaccinated.