Coronavirus Victoria: everything we know about Melbourne's Covid-19 clusters

On 2 July a stay at home order was placed on 36 suburbs from 10 postcodes across metropolitan Melbourne, due to problematic rates of coronavirus in these areas, including large clusters and community transmission.

These postcodes are 3012, 3021, 3032, 3038, 3042, 3046, 3047, 3055, 3060 and 3064.

The Victorian premier, Daniel Andrews, said the outbreaks were largely caused by gatherings of extended families stretching out across multiple households and suburbs and failures in hotel quarantine management.

On 2 July Victoria’s chief health officer Brett Sutton confirmed that Victoria had experienced 87 clusters, but not all were still active.

But what exactly do we know about these complex, interconnected clusters? How large are they, when did they start and how do they relate to each other?

While a large amount of information is protected by the government for privacy reasons, we have tried to break down everything we know about every Melbourne cluster, as of Thursday 2 July.

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Keilor Downs family 2 / Coles Chilled Distribution Centre

Area: Keilor Downs, Albanvale, Laverton – Brimbank, Wyndham LGA

Cluster declared: 19 June

Current size: 22 (Total), 17 (Family), 6 (Coles)

What we know: This is the largest family cluster, and with new cases announced as recently as Thursday, it is still very much active. It has spread across at least eight households in Melbourne, but the health department says there is no known connection between this cluster and the previous family outbreak in the same suburb.

This cluster includes a teacher at Albanvale primary school, students at Keilor View primary school and Keilor Downs College with both locations closed temporarily for cleaning.

This was the second time Keilor Downs College was closed due to the virus, and after a classmate of the infected student tested positive all students at the school were asked to get tested at the Melbourne Showgrounds, symptomatic or not.

Six cases have now also been associated with the Coles Chilled Distribution Centre in Laverton which is linked to this family cluster. Several of these workers worked while infectious and further contact tracing and testing is underway.

Albanvale primary school

Area: Albanvale-Brimbank LGA

Cluster declared: 27 June

Current size: 14

What we know: Not much is known about this cluster, first mentioned in passing in a health department update on 27 June. It’s understood that it is connected with the Keilor Downs family 2 cluster (above).

On 20 June the department confirmed a teacher at the school had tested positive to Covid-19 and was connected to the Keilor Downs family. On 22 June two more teachers were diagnosed.

On 27 June the department of health said the cluster had grown by two and was defined as a separate outbreak.

On 2 July Sutton spoke on a number of school clusters and confirmed that Victoria had seen student-to-student transmission.

Rydges hotel

Area: Melbourne city, across Melbourne

Cluster declared: 27 May

Current size: 17

What we know: This cluster is the first of two outbreaks among staff at hotels hosting quarantined returned international travellers. The cluster is made up of a handful of staff at the Rydges hotel and their close household contacts.

The exact cause of infection is still under investigation, with the Victorian chief health officer, Brett Sutton, suggesting they may never know exactly what happened.

On 6 June, one of only two days Victoria recorded no new cases, the health department was helping track the movements of a man who travelled to Queensland on 1 June via the Sky Bus and Southern Cross station while infectious. He was described as “linked to a confirmed case from the Rydges” but was not “disclosed as a close contact” and therefore was not isolating. While it appears he is connected to the cluster he is not included in the state’s official tally.

It’s been suggested by the premier that a large number of Melbourne’s cases can be linked back to hotel quarantine breaches by genomic testing, but a total number is unknown.

Stamford Plaza/Monash Health/Hallam family

Area: Melbourne, Hallam – City of Melbourne and Casey LGA

Cluster declared: 15 June (Monash Health/Hallam), 17 June (Stamford Plaza)

Current size: Eight (Monash Health/Hallam), 32 (Stamford Plaza)

What we know: When combined, these two interconnected clusters account for one of the largest outbreaks in the state, with 27 cases, but officially they are considered separate by the health department.

The Monash Health outbreak, later known as the Hallam Family outbreak, was first announced when a patient at Monash Health was linked to two more cases, a household contact and a health care worker that treated them.

By 17 June it was considered to be primarily family-based rather than connected to the clinic.

The same day a worker tested positive at the Stamford Plaza Hotel used for returned traveller quarantine. This cluster quickly grew and on 19 June it was suggested that one infected security contractor was actually a household contact of the Hallam family.

Sutton has since confirmed that it was this worker, who was infected at the hotel, brought the virus to their family and started Hallam outbreak.

It has been suggested by the premier that a large number of Melbourne’s cases can be linked back to hotel quarantine breaches by genomic testing, but a total number is unknown.

Roxburgh Park family

Area: Roxburgh Park – Hume LGA

Cluster declared: 2 July

Current size: 20

What we know: The chief health officer announced this cluster on 2 July, stating that in recent days links had been made between eight households across Melbourne.

Besides being associated with a family and centring around the northern suburb of Roxburgh Park, little is so far known about this new and significant cluster.

Coburg family

Area: Coburg, Pakenham, Moreland and Cardinia LGA

Cluster declared: 14 June

Current Size: 15

What we know: The Coburg family cluster is spread out across at least three households in Melbourne’s north and south-east, all believed to be part of one extended family.

In three days it grew from three to 12 people, and caused the temporary closure of St Dominic’s Primary School in Broadmeadows after a student tested positive and Pakenham Springs Primary School after two students were found to have Covid-19.

The most recent case associated with the cluster was announced on 26 June, bringing the total to 15.

H&M Northland/North Melbourne family/ Brimbank family

Area: Preston-Darebin LGA

Cluster declared: 18 June

Current size: Unknown, at least 30

What we know: While this cluster began as a workplace outbreak, on 25 June it was reclassified by the health department as a family cluster in the suburb of North Melbourne.

The first person diagnosed was a staff member at the H&M store who also attend the Black Lives Matter protest on 6 June, but was not considered to be infectious at the time. Two days later a second staff member contracted the virus. They also attended the protest but are believed to have been infected at the store.

By 26 June the cluster had grown to 15, the majority household contacts of a staff member.

While some reports have suggested that the “North Melbourne” in the cluster’s name refers to the region of “northern Melbourne”, the DHHS has twice confirmed to Guardian Australia that the name does, in fact, refers to the suburb of “North Melbourne”. However, this does not necessarily mean that all, or even most, associated clusters are actually located within that suburb.

On 25 June a new “Brimbank Family” cluster was declared, which grew to six cases over the next few days. On 29 June the health minister said a link had been found between this cluster and the North Melbourne outbreak.

St Monica’s College/Wollert

Area: Epping, Wollert-Whittlesea LGA

Cluster declared: 24 June

Current size: 15

What we know: This outbreak occurred in the local government area of Whittlesea, which has had comparable numbers of active cases as other council areas deemed “hotspots”. But so far the health department has not deemed Whittlesea a problem area.

The outbreak began with a staff member of St Monica’s College. By 25 June the department ruled the outbreak was primarily caused by a non-school related social gathering and renamed it the Wollert cluster.

On 26 June the deputy chief health officer confirmed a teenaged worker at a McDonald’s restaurant in Mill Park had tested positive, with deep cleaning and contact tracing being conducted. This worker is also a student at St Monica’s College but there is currently no established link between them and the Wollert social event.

Hugo Boss, Collins St

Area: Melbourne – City of Melbourne LGA

Cluster declared: 30 June

Current size: Six

What we know: Not much is known about this cluster. On 30 June it was announced that three cases were linked to the store, including at least one staff member and a household contact of the original case.

The next day an additional three cases were added.

Contact tracing, further testing and deep cleaning of the store is underway.

StarTrack, Tullamarine

Area: Tullamarine–Hume LGA

Cluster declared: 30 June

Current size: Two

What we know: StarTrack is a transport and logistics company owned by Australia Post. On 3o June the department confirmed that two workers from the facility in Tullamarine had tested positive to Covid-19.

Both worked while infectious, and deep cleaning, contact tracing and further testing is underway.

Truganina / Sunshine West / Al Taqwa College

Area: Truganina – Melton and Wyndham LGA

Cluster declared: 29 June

Current size: 15.

What we know: This cluster is actually a collection of two outbreaks, with some links through the Al Taqwa College in Truganina.

On 29 June the health department said there was a family-based cluster in Truganina with five cases associated. On the same day, the high school was also closed down for cleaning due to an associated case.

On 1 July the department said there were five additional cases among staff at Al Taqwa College, bringing the total cases to eight.

It was suggested that these cases were linked to previous outbreaks in Sunshine West and Truganina, but little detail has been given on the Sunshine West cluster.

Patterson Lakes and Lysterfield family

Area: Patterson Lakes, Lysterfield – Kingston and Knox LGA

Cluster declared: 29 June

Current size: 10

What we know: All that is known is that a family spread across the south-eastern Melbourne suburbs of Patterson Lakes and Lysterfield have contracted the virus. Further contact tracing is under way.

Springside Primary School

Area: Caroline Springs – Melton LGA

Cluster declared: 2 July

Current size: Three

What we know: All that is known is a number of people associated with the school have tested positive, including at least one student.

Further contact tracing is under way.

Ascot Vale family

Area: Moonee Valley LGA

Cluster declared: 28 June

Current size: Unknown

What we know: This cluster was first mentioned on 28 June, but no total was given. Guardian Australia has contacted the health department for clarification.

All that is known is two students, from Ascot Vale primary school and the Essendon Keilor College, Essendon campus, tested positive for Covid-19. Both students are linked to the cluster.

The schools underwent cleaning and contact tracing is under way.

Maribyrnong family

Area: Maribyrnong LGA

Cluster declared: 23 June

Current size: Five

What we know: The health department identified this new cluster with five members of the same family household testing positive to Covid-19. No further cases have been announced and investigations are ongoing into the source.

Hampstead Dental, Maidstone

Area: Maidstone-Maribyrnong LGA

Cluster declared: 24 June

Current size: Three

What we know: Three staff members have so far tested positive at the Hampstead dental clinic in Maidstone. So far no patients have been identified as close contacts. The clinic was closed temporarily for cleaning and contact tracing is still underway.

Although this cluster has previously been referred to as the Maidstone dental cluster it has no association with the Maidstone Dental Clinic which also operates in the suburb.

Related: Cedar Meats cluster: why abattoir workers are on the coronavirus frontline

Older clusters:

Keilor Downs family 1

Area: Keilor Downs – Brimbank LGA

Cluster declared: 28 May

Current size: 13

What we know: The first Keilor Downs family outbreak is one of the largest family clusters. The last additional case was announced on 31 May, suggesting this cluster may have run its course. The cluster was spread out across several households in the same family and caused the temporary closure of the Keilor Down College and Holy Eucharist Primary School in St Albans South after children in the family tested positive. A teacher had previously tested positive at Keilor Down College however the department of health said this was unconnected. Two people in the cluster also attended the Global Resource Recovery centre in Laverton causing it to be closed for cleaning.

Cedar Meats

Area: Brooklyn, Brimbank and Wyndham LGA

Cluster declared: 2 May

Current size: 111

What we know: Cedar Meats is Australia’s largest cluster. It’s believed to have begun with one worker attending the abattoir while infectious. The close conditions which knife-hands work in along the production line, along with the cold environment of the boning rooms, caused the virus to spread fast. Due to complications with who workers listed as their employers, the factory wasn’t officially told of the first diagnosed case. Cedar was alerted by the department three days later when a worker accidentally severed their thumb, then later developed Covid symptoms in hospital. When case numbers grew to four the factory was shut down and every worker was told to isolate and be tested. Within in weeks, four cases ballooned to 111, made up of 67 staff members and 44 close contacts.

McDonald’s Fawkner

Area: Fawkner – Moreland LGA

Cluster declared: 9 May

Current size: 13

What we know: This cluster began around the time of the Cedar Meats cluster, originally starting at the Fawkner McDonald’s and spreading to a worker at the Craigieburn store through household contacts. On 17 May a driver that serviced the Fawkner McDonald’s tested positive.

• Due to the unprecedented and ongoing nature of the coronavirus outbreak, this article is being regularly updated to ensure that it reflects the current situation at the date of publication. Any significant corrections made to this or previous versions of the article will continue to be footnoted in line with Guardian editorial policy.