A health expert is worried about an increase in the number of measles and mumps cases among children in Essex.
More children need to have the MMR to prevent epidemics
Sixty four cases of measles have been confirmed so far this year compared with 10 in 2006. Mumps outbreaks have spread in recent years.
Dr Alberto Dominguez, immunisation co-ordinator, said: "Affected people had not had booster doses of measles, mumps and rubella vaccination."
The doctor is calling on all parents to make sure their children are immunised.
Dr Dominguez, based at Colchester Primary Care Centre, is worried that epidemics might develop and said: "Most of the time, children with these illnesses recover well.
Outbreaks of disease
"However, serious complications such as encephalitis, meningitis and even fatalities can occur.
"Lasting damage such as impaired hearing and sterility can be caused.
"Rubella infection in the first four months of pregnancy can result in cataracts, deafness or heart defects in babies.
"I'm still often asked about the safety of MMR vaccination but there is an overwhelming body of evidence to show that it's safe and protects against measles, mumps and rubella."
The first MMR jab is given ideally at 13 months with a booster given at the age of three-and-a-half.
However, in North Essex a quarter of all children have missed the MMR (one or both doses) by the age of five.
The doctor advises parents to have their babies vaccinated at the ages of two, three and four months to protect them against diphtheria, tetanus, whooping cough and polio.
"If children and young people do not receive all of their jabs, including boosters, they are vulnerable to these diseases and outbreaks are more likely to occur," Dr Dominguez said.