PARENTS are being urged to protect their children against polio after a “wild” strain of the virus was detected in Islington’s sewage system.

Some of the 116 samples discovered in eight north London boroughs – including Islington and Camden – are of a “vaccine derived polio virus” that is ­worrying health chiefs because it can cause paralysis in unvaccinated children.

The decision to offer vaccines and boosters to all Islington children aged one to nine has been ­taken to “ensure a high level of protection from paralysis”.

The Joint Committee on Vaccination and Immunisation said they had evidence the infection was spreading across north London, particularly in areas with low vaccination rates, and that transmission had gone “beyond a close network of a few individuals”. The NHS will contact parents when it is their child’s turn for the jab or booster jab.

Dr Vanessa Saliba, a consultant epidemiologist at the UK Health Security Agency, said: “It is vital parents ensure their children are fully vaccinated for their age.

“All children aged one to nine years in London need to have a dose of polio vaccine now – whether it’s an extra booster dose or just to catch up with their routine vaccinations.

“It will ensure a high level of protection from paralysis. This may also help stop the virus spreading further.”

She added: “We know the areas in London where the polio virus is being transmitted have some of the lowest vaccination rates. This is why the virus is spreading in these communities.”

She said the UKHSA – formerly Public Health England – is in talks about the discovery with officials in New York and Israel where a young adult was paralysed by the virus.

The last case of polio in the country was in 1984 and decades ago around 8,000 people would develop paralysis from it every year.

The vaccination push follows shock findings earlier this year of the Type 2 polio virus (PV2) in Beckton sewage treatment works.

The UKHSA said that following “further upstream sampling” it had now identified positive samples “in parts of several boroughs” including Islington.

Jane Clegg, chief nurse for the NHS in London, said: “While the majority of Londoners are protected from polio, the NHS will shortly be contacting parents of eligible children aged one to nine years old to offer them a top-up dose to ensure they have maximum protection from the virus.

“We are already reaching out to parents and carers of children who aren’t up to date with their routine vaccinations, who can book a catch-up appointment with their GP surgery now and for anyone not sure of their child’s vaccination status, they can check their ‘red book’.”

Sewage surveillance has been increased to assess the extent of spread of the virus, the UKHSA said.