Measles cases in England and Wales have risen to 2,016 in 2012, the highest annual total for 18 years, says the Health Protection Agency.
The measles cases during 2012 have been associated with prolonged outbreaks in Merseyside, Surrey and Sussex.
There were also several smaller outbreaks in travelling communities.
The HPA said parents should ensure their children are fully protected against the disease with the MMR vaccine.
Dr Mary Ramsay, head of immunisation at the Health Protection Agency, said coverage of the MMR vaccine is now at historically high levels.
"But measles is highly infectious and can spread easily among communities that are poorly vaccinated, and can affect anyone who is susceptible, including toddlers in whom vaccination has been delayed."
The measles virus can spread through droplets in the air that come out of the nose and mouth when an infected person coughs or sneezes.
The initial symptoms include cold-like symptoms, red eyes which are sensitive to light, a fever and greyish white spots in the mouth and throat.
These become a red-brown spotty rash after a few days.
Dr Ramsay said older children who were not vaccinated at the routine age, who were now teenagers, were at particular risk of becoming exposed while at school.
The only way to prevent outbreaks of measles is to ensure children are being vaccinated, Dr Ramsay said.
"Measles is often associated with being a disease of the past and as a result people may be unaware that it is dangerous infection that can lead to death in severe cases.
"Parents should ensure their children are fully protected against measles, mumps and rubella with two doses of the MMR vaccine.
"Parents of unvaccinated children, as well as older teenagers and adults who may have missed MMR vaccination, should make an appointment with their GP to get vaccinated.
Professor Ian Jones, from the University of Reading's School of biological sciences, said that "the current rate of infection, which is inversely related to the level of immunisation in the population, is unacceptably high".
"The numbers have been swollen by very localised pockets of infection (eg. an epidemic in Liverpool) and for most counties rates of immunisation of over 90% are the norm, the highest in 13 years."
He said the MMR vaccine offered lifelong protection from measles, mumps and rubella.
"If the immunisation record is uncertain, for example for travellers, assume it is incomplete and have a booster - you cannot over immunise."
Measles continues to circulate in several European countries, popular with holidaymakers.
The UK along with France, Italy, Spain and Romania accounted for 87% of the total 7,392 measles cases reported throughout the European Union countries up to the end of November 2012.