The latest alert has been raised after traces of polio were found last year in sewage in east London.
An NHS vaccine “catch up” programme has been set up for children aged one to 11 who are behind schedule to get their jabs at primary schools, GP surgeries or community centres.
The programme, also including mumps and rubella vaccines, covers the eight local authority areas of Tower Hamlets, Hackney, The City, Newham, Barking and Dagenham, Waltham Forest, Redbridge and Havering.
“Polio and measles can have tragic consequences if you are not vaccinated,” Newham GP Muhammad Naqvi warned. “It can lead to serious long-term health problems. Both infections are preventable with vaccinations.”
One-in-four children in east London have not had all their jabs by the age of five, according to latest NHS data — well below the 95 per cent target set by the World Health Organisation.
The UK is said to have “a circulating form of polio” which on rare occasions can cause paralysis in those not fully immunised.
Measles cases have also risen in London, with 33 confirmed reports this year.
Parents whose children may have missed a vaccine are being contacted by the NHS through their school immunisation service by health professionals who can answer questions and arrange appointments.