Three children are among the new coronavirus cases in Victoria as Melbourne's lockdown continues.
The state announced 11 total coronavirus cases on Monday in the previous 24-hour reporting period, however two had already been identified on Sunday afternoon.
The two new cases on Sunday emerged in the Arcare Maidstone aged care facility, where a resident and registered nurse tested positive. Another staff member is among today's new cases.
Victorian Health Minister Martin Foley told reporters three of the 11 cases were linked to the Whittlsea outbreak and are household contacts of people with existing infections who have been in quarantine.
Four new cases are household contacts of the Western Melbourne outbreak, bringing the total of cases in that outbreak to 14.
Of those four cases, there are three children and one adult. All are family contacts of previous West Melbourne cases.
There are three new cases in Arcare Maidstone, bringing the total number of that outbreak to nine.
There is one new case in the Port Melbourne outbreak, bringing the total to 31.
Children infected with Delta variant
Mr Foley told reporters on Monday the three children and adult linked to the Western Melbourne outbreak have the more infectious Delta variant.
It comes after it was revealed last week a family infected with Covid who travelled to NSW's south coast also had the Delta variant, which has become the predominant one in India.
Chief Health Officer Brett Sutton said it was a "variant of concern" as the "attack rate was high" within households where there was a positive case.
"Seventy-five per cent of people within households becoming positive when there is a case, that is a challenge," he said.
"It's pretty rapidly moving."
Professor Sutton said last week there were suggestions the Delta variant caused greater illness among children and there were concerns for that reason.
He told reporters on Monday however children mostly had a mild illness or no symptoms and none have required hospitalisation.
Authorities still don't know how the Delta variant has spread in Melbourne.
Infectious diseases expert Sharon Lewin suspects the variant could have leaked from a hotel quarantine or from a returned traveller who was provided with an exemption to isolate at home.
"There are exemptions for diplomats and other people ... but those are actually really quite rare," she told 3AW radio.
"That is another source that the authorities are going to be investigating."
Will Melbourne's lockdown end on Friday?
It is unclear if the new cases will dent Melbourne's hope of emerging from lockdown on Friday but Professor Lewin remains optimistic.
"It really depends on the data that we're going to hear about today about the origin of these nine cases. But so far so good," she said.
Victoria's Deputy Chief Health Officer Allen Cheng on Sunday said he expected restrictions would be eased as planned.
"Given five per cent of Victorians have been tested in the last seven days, if there was a big outbreak going on I would expect to have picked it up," he said.
"That risk does fall over time but we are still concerned about that and that is where all our efforts are going."
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