UK detects vaccine-derived polio in London sewage

The United Kingdom’s polio-free status could be at risk for the first time in over three decades after several samples of vaccine-derived poliovirus were found during routine sewage testing.

Several closely related viruses were found in samples taken in north and east London between February and May, the UK Health Security Agency said on its website on Wednesday.

It said findings suggest some spread between closely linked individuals and the virus has continued to evolve and is now classified as a vaccine-derived poliovirus type 2.

According to the health agency, no cases of polio or associated paralysis have been reported.

“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 findings that were not detected again.

“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,” the agency said.

The health agency said it is working with other bodies, including the World Health Organisation, to urgently investigate the matter to understand the extent of the transmission.

Polio in UK

Polio is mostly spread by an infected person who does not properly wash their hands and then touches food or water ingested by someone else.

The virus thrives in the gut and emerges in the faeces of infected people. In up to One percent of patients, the virus can infect the spine and cause paralysis.

The UK’s last case of wild polio was in 1984 and the country was declared polio-free in 2003.

Wild polioviruses have been eradicated in most parts of the world except in Afghanistan and Pakistan, where they remain endemic.

“Vaccine-derived poliovirus is rare and the risk to the public overall is extremely low,” said Vanessa Saliba, consultant epidemiologist at the agency.

Ms Saliba said most of the UK population were protected from vaccination in childhood, “but in some communities with low vaccine coverage, individuals may remain at risk.”

She encouraged parents to make sure their children were vaccinated after the discovery of the virus during routine wastewater surveillance – particularly those who may have missed shots during the COVID-19 pandemic

Authorities are investigating the extent of community transmission and have established a “national incident” to check for cases elsewhere as a precaution.

Vaccination update

Jane Clegg, Chief nurse for the National Health Service (NHS) in London said the majority of Londoners are fully protected against Polio and won’t need to take any further action.

Ms Clegg said 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.

“Meanwhile, parents can also check their child’s vaccination status in their Red Book and people should contact their GP surgery to book a vaccination, should they or their child not be fully up to date,” she said.

Recent figures in London suggest immunisation coverage of 86.6 percent, according to the Global Polio Eradication Initiative.