Victoria has reported just three new locally acquired cases of coronavirus in the state's daily update this morning
The Department of Health reports 19,136 vaccine doses were administered, with 43,542 test results received.
There were no new overseas cases of the virus.
All new locally-acquired cases are linked to the current outbreaks, and all were in quarantine throughout their entire infectious period.
Meanwhile, Victorian health authorities have managed to link a mystery case of COVID-19 to current outbreaks in the state.
But they are still trying to discover how the man, who was working as a traffic controller at the Moonee Valley drive-through testing site, managed to catch the virus.
He tested positive on Wednesday, two days after developing symptoms, and his close contacts have so far tested negative.
On Thursday, Victoria's acting Chief Health Officer Ben Cowie warned authorities "may not find the smoking gun" of how he caught the virus.
It's believed the man had not been vaccinated despite being eligible as a frontline worker.
The state recorded seven local cases on Thursday, of which six have been in isolation while infectious.
Among them were four students from Bacchus Marsh College, and two household contacts linked to the Lacrosse apartments in Docklands, where 500 people are in isolation for 14 days.
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Separately, a positive case who was isolating while infectious has also been reported in the Bass Coast Shire, to be included in Friday's official tally.
Meanwhile residents of a Hawthorn apartment building have also been told to quarantine, as about 13,000 people remain in isolation across the state.
Authorities are also urging people in Balwyn, Camberwell, Canterbury, Mont Albert and Surrey Hills to get tested if they have even mild symptoms, after wastewater testing in the area showed virus fragments.