Health authorities have issued a new warning for western Sydney's measles outbreak after it was revealed the latest person to contract the disease visited several popular locations including a shopping centre and a restaurant last weekend.

The new patient brings the total number of cases associated with the recent outbreak of the potentially deadly virus to 17, NSW Health said in a statement.

In total, there have been 23 people who have contracted the disease in NSW so far this year.

The patient visited busy locations across the city last weekend, including:

* Powerhouse Museum – 14 April, early afternoon

* Rashays restaurant, Darling Harbour – 14 April, later in the afternoon

* Liverpool Westfield, including an optometry practice on 13, 15 and 17 April

* Blacktown Hospital – 15 April, approximately 7.30pm – 8.00pm

* Casula Central Medical Practice and Chemist Warehouse, Casula – 18 April, approximately 10.00am.

The western Sydney outbreak was initially sparked by a traveller returning from Indonesia.

Sydney's western suburbs have some of the lowest rates of immunisation in Australia.

In Parramatta and the surrounding suburbs, nearly a quarter of one-year-olds aren't fully vaccinated.

That contrasts with the inner west suburbs of Newtown and Enmore, where four per cent are unprotected, data from the National Health Performance Authority shows.

NSW Health has specifically urged people in their 20s, 30s and 40s to check their measles vaccination status, because they may not have been fully vaccinated.

“Investigations indicate the latest person to contract measles only had one dose of the vaccine and this person falls into the 20s, 30s and 40s age bracket,” Dr Vicky Sheppeard, Director of Communicable Diseases, said.

“We are urging all people in this age bracket to check their vaccination history and have the measles vaccine if they do not have a record of having received two doses previously. Don’t assume you are covered unless you have written records of two doses. It is perfectly safe to have the measles vaccine again, if you are not sure whether you’ve had two doses of the vaccination in the past. The vaccine is free to people in this age group through GPS.”

Dr Sheppeard said it was important for people to watch for symptoms, arrange to see the GP if concerned, and limit exposure to others until the GP has made a diagnosis.

“Our public health units are contacting people known to have been in those locations to offer preventive injections, as appropriate. However it will not be possible to identify and contact all people who may have been exposed to the disease.

“Measles is highly contagious and is spread in the air through coughing or sneezing by someone who is unwell with the disease.”

For more information on the measles outbreak, visit this link .

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