A school at the centre of a measles outbreak in which two pupils were hospitalised will be immunising children at risk of contracting the disease.

Twelve children at Broadfields Primary School, in Broadfields Avenue, Edgware, have been reported to have measles, two of whom had to go to hospital because of lung complications.

One seven-year-old boy had to be put on a ventilator because of breathing difficulties but he has now returned to school.

About a quarter of the children at the school remain susceptible to the highly infectious disease because they have not had two doses of the measles, mumps and rubella (MMR) vaccine, which gives between 95 per cent and 99 per cent protection.

To prevent any further spread of the disease, the school has linked up with Barnet Primary Care Trust (PCT) and Barnet Council to run a special MMR immunisation session for these at-risk children.

There will also be a meeting today for parents to discuss the issue with health specialists from the trust and the Health Protection Agency.

The measles virus infection can cause middle ear infections and pneumonia, among other conditions, and can be severe enough to need hospitalisation.

Dr Andrew Burnett, medical director for Barnet PCT, urged parents to have their children protected against measles. He said: "This very infectious disease has recently caused two Barnet children to need specialist hospital treatment, and I want to stop this disease in its tracks. Measles is preventable. Two doses of MMR vaccine will protect children against measles and mumps and will stop future babies suffering from congenital rubella syndrome."

Typical symptoms of the disease include fever, coughing, red and painful eyes, swollen glands, loss of appetite and a rash, which tends to follow three to four days after the previous symptoms.

People contracting measles are infectious from just before the time they become unwell to around four days after the onset of the rash. Those affected should stay off school or work for five days from the onset of the rash.