- Video report by ITV News Reporter Martha Fairlie
Estimates show 1 in 7 five-year-olds are not fully immunised against MMR as the World Health Organisation (WHO) confirms the UK is no longer 'measles free.'
The figures from Public Health England (PHE) come as hundreds of thousands of children prepare to start primary school in the next few weeks.
New estimates show around 30,000 (around 1 in 19) five-year-olds have not received their first dose of MMR, which protects against Measles, Mumps and Rubella, usually given to children at 12 months.
But more children have not been given their second MMR dose.
PHE said 90,000 (around 1 in 7) five-year-olds have not been given the second injection, recommended at 3 years and 4 months, meaning they are not fully immunised.
Two doses of MMR in a lifetime are needed for a person to be considered fully protected.
Almost a third of these children are in London, so around 1 in 4 primary school starters in the capital do not have the full protection that the MMR vaccine offers.
The estimates, part of PHE's Value of Vaccines campaign, mean more than 5% of five year olds are starting reception year having not received any MMR.
This leaves them at high risk of measles at a time when outbreaks of the disease are at an all time high.
Prime Minister Boris Johnson has called for urgent action to boost vaccination rates, following the rise in cases of measles.
There were 231 confirmed cases of the disease in the UK during the first quarter of 2019.
The prime minister has called for health leaders to renew their efforts to ensure 95% of the population have had both doses of the MMR vaccine.
Ahead of a visit to a hospital in the south-west, Mr Johnson said: "After a period of progress where we were once able to declare Britain measles free, we've now seen hundreds of cases of measles in the UK this year.
"One case of this horrible disease is too many, and I am determined to step up our efforts to tackle its spread.
"This is a global challenge and there's a number of reasons why people don't get themselves or their children the vaccines they need, but we need decisive action across our health service and society to make sure communities are properly immunised."
The WHO has confirmed the UK no longer holds a 'measles free' status, three years after it was eliminated in the country.
Dr Mary Ramsay, Head of Immunisation at PHE, said: "We’re continuing to see outbreaks of [measles] occurring in communities across the country, many linked to visiting European countries over the summer holidays.
"The vast majority of those affected are not fully immunised and vaccine preventable diseases spread more easily in schools.
"It’s crucial that children have maximum protection as they begin to mix with other children at the start of their school journey."
Fiona Doyle, runs Little Ladybirds Day Nursery in Finchley, London and she bans children from attending her nursery who have not had the right vaccinations.
She told ITV News: "We make sure every child that comes through this nursery is vaccinated, we check through their health record, which is a red book, the reason why we do it is to make sure every child is safe in this community, in our nursery community.
"It's a matter of social responsibility...there are people who can't be vaccinated, so it's up to the people who can be vaccinated to ensure that they are."
She added: "I think it gets to a point, like other countries in the world, where it is compulsory and if you don't have your child vaccinated, you perhaps don't have access to schools, nurseries or playgroups that people who are vaccinated have access to."
Figures also show around 100,000 (1 in 8) five-year-olds in England may still need their 4-in-1 pre-school booster that protects against diphtheria, whooping cough, tetanus and polio.
Dr Mary Ramsay, Head of Immunisation at PHE, said: “It’s a real concern that so many young children – as many as a quarter of a reception class in some areas - could be starting school without the full protection that the NHS childhood immunisation programme offers for free.
"We’re urging all parents of primary school starters to check their child’s Red Book now to make sure there is a record of two MMR doses and the 4-in-1 booster vaccine."
To check that your child has received all their vaccines on schedule, click here and refer to your child’s Red Book.
If in any doubt, contact your GP practice.