Parents in north Wales are being urged to act quickly to get their children vaccinated against measles.
It comes as the Betsi Cadwaladr University Health Board confirm that more than 10,000 young people have not received two doses of the MMR vaccine in north Wales.
Although the outbreak is at present affecting the Swansea, Neath, Port Talbot and Llanelli areas, it is likely to spread to other areas.
The likelihood that unvaccinated children across the country will come into contact with those already infected is high.
It is vital that parents act now to ensure that their children are fully immunised with the MMR vaccine.
More than 60 people contracted the disease in an outbreak that started in Porthmadog in 2012.
2013 is expected to be the worst year for measles in the UK for the past two decades. Read more about the illness and how it is treated.
If the Government's top adviser on immunisation thinks the risk of an emergency in England is a possibility, I believe him.