Thousands of children in Gloucestershire are not fully protected against measles.
The warning comes as cases of the illness continue to increase in Gloucestershire.
Figures released last week by Public Health England have confirmed 57 cases of measles between January and April 2013 in Gloucestershire, compared to three for the same period in 2012.
It is estimated that5,932 children aged between 10 and 16 years old in Gloucestershire have not had both doses of the recommended two MMR vaccinations.
