Victoria has reported 57 new local COVID-19 cases of whom 44 were in isolation for the entirety of their infectious period, but an epidemiologist from the Royal Melbourne Hospital (RMH) explains how wastewater tests show signs the virus may be circulating under the radar.
Professor Benjamin Cowie of the RMH and the Peter Doherty Institute for Infection and Immunity highlights continued "unexpected detections" of COVID-19 in the wastewater system.
"While the testing program isn't necessarily a smoking gun, it does provide a really good signal and another line of intelligence for us to follow," Cowie told a press conference this morning.
"So we began targeted wastewater surveillance in high rise public housing towers and then received a detection at a complex at 480 Lygon Street in Carlton several days ago," he said.
"Based on that signal alone, we made the entire complex effectively a tier two exposure site and encouraged all the residents to get tested, and we uncovered a case living inside the building."
As a result, Cowie said authorities were able to provide that person with care and treatment, and to prevent other transmission, which he said demonstrated the potential use of use of wastewater detection as an "advanced warning system".
Often it is a case of someone shedding while no longer infectious, or epidemiologists know of someone who has COVID-19 and is isolating in the area connected to the sewage result, but at times the source is a mystery.
"That's when we really pay close attention," Cowie said.
"We have a few of these signals alerting us right now. In regional Victoria, we've seen three detections in Shepparton with our period of concern being between the 9th and the 16th of August, and I know the community in Shepparton has come out - testing numbers have increased substantially over the last few days."
There have also been wastewater detections in Lakes Entrance with a period of concern from 8-11 August, in Ardeer from 11-16 August, and new detections in the suburbs of Albion, Braybrook, St Albans, Sunshine, Sunshine North, Sunshine West and Tottenham from 15-17 August.
"And we've had three detections in some southeastern suburbs, including Dingley Village, Keysborough, Noble Park, Springvale and Springvalue South, with a period of concern being between the 11th and the 17th of August."
Photo: Professor Benjamin Cowie of the RMH and the Peter Doherty Institute for Infection and Immunity
But the expert said of possibly the greatest concern was the strong and repeated detections from an industrial precinct in Sunshine West.
"Now, that's an area where nobody resides, there's no one living there, but a lot of people work there," he said.
"We've been working with businesses in this precinct on surveillance testing for the last few days, and we haven't uncovered any cases at this point, but essentially we're at the point where based on these repeat, strong detections, it becomes more likely than not that someone who works in this area actually does have coronavirus infection.
"That is clearly of concern to get them tested so we can look after them and provide them appropriate treatment and care, but to protect their colleagues and indeed the entire community. So my message is that if you work in that industrial precinct come forward to be tested now, even if you don't have symptoms."
Of today's 57 new cases reported, 54 are linked to known outbreaks, mostly Al-Taqwa College students and close contacts from that school outbreak.
"So we might see further cases that are exactly the same as a result of day 13 testing," Premier Daniel Andrews said.
"There are some 296 active cases across the state, 16 people are in hospital, three of those in ICU and I'm told one of those is on a ventilator.
"There were just under 50,000 test results received overnight," Andrews said, adding this was a significant uplift on numbers which were low a few days ago.
More drive-through vaccination clinics for Victoria
The Premier said 27,581 Victorians were vaccinated yesterday, taking the number of doses in the state to 2,050,042 in state-run centres.
Following the opening of Australia's first drive-through vaccination hub in Melton there have been around 1,200 doses administered at the site, and now the government will be opening up three more centres in this format.
The Premier has announced the new drive through clinics will open at the Former Ford Factory in Broadmeadows, at Sandown Racecourse in Springvale and at the Eagle Stadium in Werribee.
The new site at the Ford Factory in Broadmeadows will be soft launched this Sunday by invitation only, and will open to the public for booked appointments from Monday 23 August.
The Sandown Racecourse clinic will be adjacent to the existing Sandown Racecourse indoor vaccination hub and will run an invitation-only soft launch on Friday. It will open to the public for booked appointments from Saturday 21 August.
Combined, these sites will have 36 bays for drive-through but have the capacity to be ramped up if needed. Victorians will be able to make bookings online or through the Coronavirus hotline, which the government says are essential.
The new site at the Eagle Stadium in Werribee will have room for both drive through and indoor vaccinations, with an expected opening towards the end of the week.
In addition, a pop-up vaccination centre opened yesterday at Peanut Farm Reserve in St Kilda. It is a walk-in, no-booking site designed for locals who are eligible for the vaccine. It administered 170 doses in its first two hours. It will operate 9am to 5pm daily for the next week. Primary Close Contacts or people with symptoms cannot attend.
There are 300,000 COVID-19 vaccine appointments available over the next four weeks and just over 80,000 Pfizer second dose appointments available.
"There are a million things that we miss about life before the pandemic and a million things we’re looking forward to doing again once we’re through this outbreak – each of those is a reason to get vaccinated," Premier Andrews said.
"We’re imploring every single Victorian to come forward and get vaccinated as soon as you can – there’s appointments available and we need you to fill them."
"Getting vaccinated is our way out of this pandemic. These new drive through clinics are convenient and easy to access – Victorians should take full advantage of them to get themselves and their loved ones vaccinated," Health Minister Martin Foley added.
Updated at 12:34pm AEST on 19 August 2021.
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