Health officials are urging anyone who has not had two MMR vaccinations to visit their doctor and get a booster jab.
Public Health England, backed by Essex County Council, is encouraging residents to check with their GP whether they've had two doses of the vaccine to protect themselves against this highly infectious disease.
Essex County Council's director of public health, Dr Mike Gogarty, said: "The only way to prevent a measles outbreak in Essex is to make sure there is good uptake of the MMR [Measles, Mumps and Rubella] vaccine across all ages.
"Parents should ensure their children are fully protected against measles, mumps and rubella with two doses of the MMR vaccine.
"The current rise in measles cases can be attributed to the proportion of largely ten to 16-year-olds who are unprotected because they missed out on vaccination in the late 1990s and early 2000s, when concern around a now disproved link between autism and the MMR vaccine was widespread.
"It is never too late to get vaccinated against measles. I would encourage parents of unvaccinated children, as well as older teenagers and young adults who may have missed MMR vaccination to make an appointment with their GP to get vaccinated as soon as possible.
"If you are unsure whether you or your child has had two doses of the vaccine, speak to your GP who will have a record.
Normally the first MMR vaccine is given as a child at 12 to 13 months old, and then a booster dose is given before a child starts school - usually around three years of age.
Experts believe the current rise in measles cases is largely due to the proportion of children now aged ten to 16 years old who missed out on vaccination in the late 1990s and early 2000s, when concern around the now undermined link between autism and the MMR vaccine was rife.
The World Health Organisation recommends that having more than 95 per cent of children vaccinated will prevent outbreaks.
Vaccination coverage for MMR across Essex at age two is approximately 93 per cent and at age five is approximately 89 per cent.
This is not the required 95 per cent - therefore there is a group of people vulnerable to getting measles and passing it to others.
Many of the recent cases are in older children and it is this age group it is believed are most at risk and who should check their vaccinations are up to date.
Although only some areas of the country have been affected so far, most areas like Essex have enough older children at risk to sustain an outbreak.
There have been two confirmed cases of measles in Essex since the start of the year.
