Suspected measles cases 'hit more than 300' as outbreak sweeps north London, leaked report reveals
Cases were detected between 20 January and 7 February, the 'sensitive' document states.
More than 300 suspected cases of measles have been detected following an outbreak in a north London school, a leaked document has revealed.
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A suspected 340 cases have been detected at a single school in Enfield, north London, according to a report by the UK Health Security Agency.
Cases were detected between 20 January and 7 February this year, the document, marked “official sensitive, states.
The latest figures come after health chiefs warned the actual number could be much higher because of a time lag on lab testing.
Dr Vanessa Saliba, consultant epidemiologist at UKHSA, said the outbreak is still mostly affecting unvaccinated children under 10 in schools and nurseries.
She said: "With the time lag involved with confirming cases through laboratory testing, we expect the actual number of cases to be higher.
"The outbreak has led to some children having to be hospitalised.”
Read more: Measles cases continue to rise as outbreak sweeps north London
Officials have urged parents to ensure their children are properly vaccinated to prevent the virus spreading further.
Dr Vanessa Saliba added: "Measles is a nasty illness for any child, but for some it can lead to serious long term complications and tragically death, but is so easily preventable with two doses of the MMRV vaccine.
"All parents want what is best for their child - if they have missed any of their doses or you're unsure, get in touch with your GP surgery. It's never too late to catch up.
"The MMRV vaccine will give them the vital protection they need against this highly contagious disease, but also help protect more vulnerable children around them who are too young or unable to have the vaccine due to a weakened immune system."
Last week, the government announced it will be providing “additional support” to GPs to protect children from life‑threatening diseases amid the measles outbreak.
The worst cases of the disease have seen children in hospital fighting “a serious but preventable disease”, the Department of Health and Social Care (DHSC) said.
Secretary of State for Health and Social Care Wes Streeting said the outbreak is "entirely preventable" and the measures would reduce the risk of further issues.
In a drive to get children vaccinated, he said: “Vaccinations are safe and they save lives.
“The return of diseases we thought we’d defeated, with children in hospital as a result, is entirely preventable."
He went on to say the investment would help GPs to protect children, and help to prevent further outbreaks like the one in Enfield.
“Every child deserves a healthy, happy start to life.”
Measles is a highly infectious viral illness that can spread very easily among people who are not fully vaccinated.
While many people recover, the illness can lead to serious complications such as pneumonia, brain inflammation and, in rare cases, long-term disability or death.
Last week, a number of other counties also issued warnings to parents.
Southend City Council said rising cases in Enfield mean they are "likely to reach Essex, Southend and Thurrock" and urged parents to check if their children are protected.
The outbreak comes after the World Health Organisation (WHO) said that the UK is no longer considered to have eliminated measles. The announcement in January follows a plateau in vaccination coverage and a surge in cases, with 3,681 cases recorded in the UK in 2024.
The latest UKHSA data shows that 91.9% of five-year-olds had received one dose of the MMR (measles, mumps and rubella) vaccine in England in 2024/25, unchanged from 2023/24 and the lowest level since 2010/11.
Just 83.7% of five-year-olds had received both MMR doses, down year-on-year from 83.9% and the lowest level since 2009/10.