People are being urged to ensure their polio vaccines are up to date after an outbreak of the virus was detected in UK sewage samples. Polio, which was officially eradicated in the UK in 2003, can cause paralysis in rare cases and can be life-threatening.
The UK Heath Security Agency (UKHSA), working with the Medicines and Healthcare products Regulatory Agency (MHRA), has found polio in sewage samples collected from the London Beckton Sewage Treatment Works. While it is normal for the virus to be picked up as isolated cases and not detected again, experts have raised the alarm after several genetically-linked viruses were found in samples between February and May.
Previously, the virus has been picked up when a person 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. However, the virus in the recent samples has evolved in England and is now classified as a ‘vaccine-derived’ poliovirus type 2 (VDPV2).
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The UKHSA is working on the theory that a person vaccinated abroad with the polio vaccine – possibly in Afghanistan, Pakistan or Nigeria – entered the UK early in 2022 and was shedding the virus. Experts are looking at the possibility that just one family or extended family may be affected, though it is unclear how many people need to be infected for polio to be detected in sewage samples.
The UKHSA stressed that the virus has only been detected in sewage samples and no cases of paralysis have been reported. It is now investigating the extent of community transmission and has established a “national incident” to check for cases elsewhere as a precaution.
Dr Vanessa Saliba, consultant epidemiologist at UKHSA, said: “Vaccine-derived poliovirus is rare and the risk to the public overall is extremely low.
“Vaccine-derived poliovirus has the potential to spread, particularly in communities where vaccine uptake is lower. On rare occasions it can cause paralysis in people who are not fully vaccinated so if you or your child are not up to date with your polio vaccinations it’s important you contact your GP to catch up or, if unsure, check your red book.
“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.
“We are urgently investigating to better understand the extent of this transmission and the NHS has been asked to swiftly report any suspected cases to the UKHSA, though no cases have been reported or confirmed so far.”
Most people who get polio do not have symptoms but some suffer mild, flu-like issues such as a high temperature, extreme tiredness, headaches, vomiting, a stiff neck and muscle pain. In one in 100 to one in 1,000 infections, the polio virus attacks the nerves in the spine and base of the brain.
This can cause paralysis, usually in the legs, that develops over hours or days. If the breathing muscles are affected, polio can be life-threatening. Medics have now been alerted by UKHSA to look out for signs of polio paralysis. The last case of natural polio infection acquired in the UK was in 1984.
