A catch-up vaccination programme has been announced to prevent the spread of a measles outbreak.
Public Health England, NHS England and the Department of Health announced last week the intention to vaccinated one million children who missed MMR jabs.
More than 1,000 cases of measles have been recorded in Swansea alone during the outbreak, with 50 cases of measles in Yorkshire and the Humber during the first three months of this year.
In 2012, there were 152 cases over the whole year, and just 62 cases in 2011.
The aim of the programme is to prevent measles by vaccinating as many children aged between 10 and 16 who either missed the MMR vaccine completely, or were only partially vaccinated in time for the next school year.
There are fears that a generation of children have low levels of protection after the MMR scare in the 1990s.
The catch-up campaign, run through GPs, schools and community groups, is expected to cost £20m and the Department of Health already has 1.2m vaccines ready to go.
Typical symptoms of measles include fever, cough, conjunctivitis and a rash. Complications include ear infections, vomiting and diarrhoea, pneumonia and meningitis.