Two more measles cases in Sydney

A health alert has been issued after two more people caught measles in Sydney taking to nine the number of people who have acquired the infection in NSW since Christmas.

The latest cases involved two people aged between 20 and 55, NSW Health said in a statement on Thursday.

"We know many adults in this age group have only had one dose of measles vaccine," communicable diseases acting director Dr Christine Selvey said.

"Anyone unsure of their vaccination history should see their GP for another dose which is free of charge."

The number of recent cases in and around Sydney means people may have been exposed locally and could be developing symptoms, Dr Selvey said.

Those symptoms include a fever, cough, runny nose and sore red eyes, followed three to four days later by a red spotty rash, which starts on the head and spreads to the rest of the body.

"Anyone experiencing these symptoms should seek medical attention and should call their doctor or emergency department before attending so that spread of measles to others in the waiting room can be prevented."

The latest people with the disease visited Chargrill Charlie's in Drummoyne on Monday night.

People at high risk of measles complications include babies who are too young for routine measles vaccination, pregnant women who haven't had their shots and people with a weakened immune system due to illness or treatment.