Doctors were on Tuesday urged to keep a close watch on children for measles symptoms following a resurgence of the once rare disease.
The Royal College of Paediatrics and Child Health has issued new national guidance on the treatment of the virus and called on the Government to urgently publish its national vaccination strategy.
Measles is an infection that spreads very easily and can cause serious health problems, including meningitis and pneumonia. It usually starts with cold-like symptoms, followed by a rash a few days later.
A total of 149 cases were reported between January 1 and September 30 this year, with 60 per cent diagnosed in London.
In its updated guidance, the RCPCH said that many paediatricians would not have previously seen symptoms associated with measles in their careers and urged doctors to check the immunisation status of all children attending hospital.
Dr Camilla Kingdon, President of the RCPCH, said: "Having to consider measles in our national guidance for the first time in decades is a disappointing but necessary move. Vaccination coverage for children under the age of 5 is now the lowest it has ever been in the past 10 years. We are already starting to see the effects of this with measles outbreaks occurring in London, Wales and Leicester.
"Many paediatricians I know live in fear of potential measles outbreaks this winter. The winter period is always an extremely tough time for all health care professionals, with high surges in RSV and influenza, as well as circulating Covid-19 and Group A Strep. To add another highly contagious and dangerous disease into the mix would be disastrous and could bring our already fragile system to its knees.
"We now find ourselves once again asking the Government, where is the long-awaited vaccination strategy? The UK Government must acknowledge these low uptake figures and focus its attention on ensuring equal access to vaccinations across all regions and socioeconomic groups."
The UK Health Security Agency in July warned that the risk of an outbreak in the capital was “primarily due to low vaccination rates over several years”, particularly in some areas and groups where coverage of the first MMR dose at 2 years of age is as low as 69.5 per cent.
The MMR vaccine is given to children to protect against measles, mumps and rubella as part of the NHS routine vaccination schedule. Children receive their first dose aged 1, and their second dose aged 3 years and 4 months
Just 75 per cent of children in the capital had received both doses of their MMR vaccine by the age of five as of March, by far the lowest proportion of any region in the country.
In Hackney, just 56 per of children had received both jabs - the lowest rate in the country.
She added: "Vaccine hesitancy is an issue, but there are real problems with accessibility that are also at play. We know that there are significant inequalities in vaccine uptake by ethnicity, deprivation and geography. This has to be addressed."
Health officials have warned that the capital could see an outbreak of up to 160,000 cases due to low vaccination levels. In July, Barnet and Haringey Council wrote to parents to warn that children who are not vaccinated against measles may need to self-isolate for 21 days if a classmate is infected with the disease.
Anyone with measles symptoms is advised to stay at home and phone their GP or NHS 111 for advice, before visiting the surgery or A&E, to prevent the illness spreading further.