(CNN) Two babies, aged 8 and 11 months, have been infected in a rare outbreak of measles in Australia as the highly contagious disease makes a comeback in East Asia and the Pacific.

Health authorities in New South Wales state said the infants likely caught the disease in public places.

They are too young to be vaccinated, Vicky Sheppeard, NSW Health's director of communicable diseases, told CNN. The standard vaccination schedule in Australia starts at 12 months. Infants lose their maternal immunity by about 6 months of age, so are vulnerable for around another six months.

NSW Health said the younger child likely became infected in the central Haymarket area of Sydney between the 26th and 30th of March, while the 11-month-old is believed to have become infected in the northern suburban Eastwood area between the 23rd and 30th of March.

Sheppeard said the locations "do not pose an ongoing risk" of infection but anyone who may be susceptible to the disease should contact a doctor. The state has seen 23 confirmed cases of measles so far this year.

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