Victoria has recorded four new locally acquired COVID-19 cases as residents of a Richmond apartment building are told to self-isolate.
All of Sunday's cases are linked to the state's current outbreaks and all were in quarantine throughout their infectious period.
But acting COVID-19 commander Naomi Bromley said people in a Richmond apartment building had been told to self-isolate for 14 days after being linked to a virus-positive case.
The stay-at-home order affects around 20 residents at the building.
Health officials say Victoria administered 15,841 vaccine doses in the 24 hours to Saturday evening and processed 25,779 virus tests.
Sunday's numbers follow two cases reported on Saturday, one quarantined during their infectious period and the other a colleague of a Melbourne testing site worker at Moonee Valley Racecourse who was briefly in the community before isolating.
There are eight people in hospital in Victoria, including three in ICU and one on a ventilator.
'We know this vaccine works'
The state's chief health officer Brett Sutton said only 10 of the 204 people who tested positive to COVID-19 in Victoria last month were fully vaccinated, and none of them were in hospital.
"All were either completely without symptoms or have mild symptoms," he said on Sunday. "We know this vaccine works. We know not everyone is yet eligible but to emphasise, for those currently eligible... it really is an additional protection to go out and get one vaccine and certainly to complete that vaccine schedule.
"We know it reduces your risk of getting COVID-19, and especially of getting very sick from COVID-19. It is increasingly compelling evidence from around the world where hundreds of millions, indeed, billions of vaccines have been given globally."
Authorities still investigating Moonee Valley case
The numbers follow two cases reported on Saturday, one quarantined during their infectious period and the other a colleague of a Melbourne testing site worker at Moonee Valley Racecourse who was briefly in the community before isolating.
Health Minister Martin Foley said on Saturday the fellow traffic controller shared a lift after work with the first, whose diagnosis was confirmed this week.
"He (the second traffic controller) was isolated as soon as he was identified as close contact and didn't have much time in the community," he said.
He visited Devon Plaza shopping centre in Doncaster on 28 July, so anyone there between 10.20am and 11.25am should isolate and get tested, he said.
Authorities were still investigating how the first Moonee Valley worker contracted the virus.
Initial results from genomic testing have linked the case to the outbreak at Maribyrnong's Ariele apartment complex sparked by a crew of NSW removalists.
However as of Saturday no origin for the Frankston man's infection with the Delta strain had been established.
He visited his partner at a Newport apartment building while infectious and it is a close contact of this person who was the second positive case recorded on Saturday.
Meanwhile Victoria's now more than one million fully vaccinated residents mean a slight change to the Pfizer jab rollout in its state-run clinics.
As of Monday all people who receive a first dose of Pfizer will wait six weeks - not three - for their second dose.
The delayed second dose is the same strategy being used in Sydney to protect more of the population faster and has also been done in the UK and Canada.
GP clinics run by the Commonwealth will continue to administer second Pfizer doses three weeks after the first dose.
Victoria is living under relaxed restrictions since coming out of its fifth lockdown, however private gatherings are not yet permitted and strict mask-wearing applies.
