Cases of measles in the first five months of this year have surpassed the number for the whole of 2010, according to new data.
The Health Protection Agency (HPA) reported 496 cases of measles in England and Wales up to the end of May this year, compared with 374 for the whole of 2010.
Most cases were in London and the South East, and children and teenagers were most commonly affected.
Small outbreaks have occurred in universities, schools and families, and there have been links with travel abroad after a surge in cases across Europe.
HPA data also show a rise in the proportion of children having the combined measles, mumps and rubella (MMR) vaccine.
The first MMR vaccination is given when youngsters are around 13 months of age, with a booster jab before they start school (usually between the ages of three and five).
Among youngsters aged two, quarterly figures for January to March show 90% had received their first jab - the highest level for 13 years and a 0.6% rise on the previous quarter.
The figures showed that by the age of five, 92.8% of children had received their first dose.
However, not all parents take their child back for the second dose. Among children aged five at the start of the year, only 85.1% had received both doses.
Dr Mary Ramsay, head of the immunisation department at the HPA, said: "We're very encouraged to see that UK MMR uptake has reached 90% in children aged two, indicating increasing levels of trust by parents in the immunisation programme.
"We're on the way to reaching our goal of 95% uptake. But anyone who missed out on MMR as a child will continue to be at risk of measles, which explains why we are seeing these new cases in a broad age range.
"It's that time of year when children are travelling on school trips and family holidays and we are reminding parents and young adults of the importance of immunisation before they travel.
"We cannot stress enough that measles is serious and in some cases it can be fatal."