Parents whose children haven't had the MMR vaccine are being urged to book a GP appointment as soon as possible.
The advice is because of a outbreak of measles in the UK.
Doctors have been put on high alert for measles, because of a resurgence of the disease.
This month, for the first time in decades, the Royal College of Paediatrics and Child Health (RCPCH) issued national guidance
It's in response to UK vaccination rates being at the lowest for a decade, at 84.5%.
Nearly three times the number of cases of measles were diagnosed in England between January and September 2023 (149), compared to the whole of last year (54)
Here in Jersey, vaccine rates are on target to reach the World Health Organisation recommended 95% this year, and there have been no recorded cases of measles since 2019.
However, Deputy Director of Public Health Grace Norman says it is vital all children are full protected and should have both doses of the MMR jab - the first before the age of two and the second before they turn five.
"The MMR vaccine is the best defence against serious infection, so I urge all parents to make sure their children are as protected as possible. If your child has not yet had the MMR vaccine or hasn’t had both doses, you should call your GP and book an appointment as soon as possible.”
Parents can check their child's vaccination status in their red book, or by contacting the Immunisations Nurse Specialist on 01534 445790.
The main symptoms of measles are a fever and a rash, but the virus can cause serious illness, including meningitis.

Fort Regent vision 'was never matched' by a budget that could deliver it, says JHA
Buzzing! Bears and Bees coming to Jersey
JCG Year 7 Choir learn and perform wartime song
Gas bills to go up by 5% in December
Second memorial plaque vandalised at Millennium Park
'They got our hopes up': Young islanders disappointed as Fort Regent plans stall
Electricity prices in Jersey to rise by 2.5%
Minister says he has been 'slated' and his family taken 'abusive' phone-calls over economic growth comments