A group of 21 un-vaccinated children have been banned from attending Princes Hill Primary School until next month after two students, both believed to have been un-vaccinated, tested positive to measles. Melbourne's measles outbreak has now risen to 15 confirmed cases. They were among the five cases on Tuesday, which also included three adults, two from the inner north where the outbreak started, and the third, which was the first reported case in Melbourne's east. Health authorities have not released details of the eastern suburbs outbreak, instead cautioning that everybody should be on alert for signs and symptoms. The outbreak started when four unrelated people - men and women aged in their 20s and a woman in her 40s - from Brunswick and Brunswick East - tested positive for measles two weeks ago.

On Monday, five new measles cases emerged - three women and two men all aged in their 20s and 30s and linked to the suburbs of Brunswick, Brunswick West and Preston The excluded Princes Hill students are being schooled from home and, along with any teachers who cannot prove immunity, will only be allowed back to classes on March 1. There was also a scare at Footscray West Primary School yesterday when the principal sent a note to parents advising that a student had contracted the illness but this child has since been found not to have measles. "We have been working with the Department of Health and Human Services, the family involved and their doctor to evaluate the situation," Principal Brendan Millar wrote in an update on Wednesday. "Fortunately, we may now report that the child's condition has been reassessed and I can confirm that the student concerned does not have the measles."

Victoria's acting Chief Health Officer Roscoe Taylor warned that, given measles has an incubation period of up to 18 days, new cases could still emerge, with people remaining infectious for many days without realising it. Australian Medical Association Victorian branch president Tony Bartone​ said the outbreak was "a huge concern", particularly when some suburbs affected did not have 95 per cent immunisation rates - enough to create herd immunity. The most recent data from the National Health Performance Authority shows none of the suburbs identified so far have 95 per cent vaccination rates for one-year-olds and five-year-olds. Dr Bartone said given children had been infectious in recent weeks, it was highly likely that more cases would emerge. "We know it's spread by sneezing, it's spread by respiratory droplets ... it can survive on surfaces outside of the body for a couple of hours," he said. Measles usually begins with common cold symptoms such as fever, sore throat, red eyes and a cough, Dr Taylor said.

Its characteristic rash usually begins 3-7 days after the first symptoms, generally starting on the face and then spreading to the rest of the body. "Anyone developing these symptoms is advised to ring ahead to their doctor or hospital and alert them that they have fever and a rash," said Dr Taylor. The measles vaccine (given as a combination with other vaccines) is recommended as a two-dose schedule for children between 12 months and four years of age. Women aged in their 20s to 40s can get a free combined measles, mumps and rubella vaccine under the Victorian government's initiative to ensure women of child-bearing age are protected against rubella. People aged under 20 can also get the vaccine under the federal government's catch-up campaign.