Victoria has recorded four new local COVID-19 cases as authorities scramble to find the source of the state’s Delta strain cluster, previously known as the Indian strain of the novel coronavirus.
The Department of Health reported the cases along with six overseas acquired infections on Sunday, as Melbourne endures its second weekend of lockdown.
The ten total cases, from almost 30,000 tests, take the number of active infections in the state to 87.
It is not yet clear whether the new infections are linked as Victorian contact tracers continue to try and to track down the source of another two “mystery” cases.
Two cases were a couple, who have been infectious in the community. They were among five new local cases reported in the state on Saturday.
One of the pair had been a regular visitor to Craigieburn Central shopping centre and came forward for testing as a result of health department efforts to test heavily in the area.
That person’s partner is the other unlinked case and is a construction worker, which has prompted the closure of a Melbourne building site, affecting 170 workers who are now all considered primary close contacts.
“Seven positive cases entered the Craigieburn shopping centre on different days and contact tracers are working to ascertain the man’s exact movements to see if they overlap with any of them,” testing commander Jeroen Weimar said.
The other three cases recorded on Saturday were less concerning, authorities said, because they were all primary close contacts of confirmed cases and had been quarantining during their entire infectious period.
Among these three cases are two Delta strain cases—a child of a family already infected with the virus, and a family friend. That cluster appears separate to the rest of the Melbourne outbreak, which is made of the Kappa strain, which like the Delta strain has caused havoc in the UK and India.
Experts still don’t know how the Delta strain entered the community and have been analysing genomic sequencing from across the country in the hope of finding a match.
Professor Sharon Lewin from Victoria’s genomic sequencing centre, the Doherty Institute, said there was no evidence pointing to the Victorian family picking up the virus while on holiday in NSW.
Rather, her “strong hypothesis” is that it entered the community via hotel quarantine.
The other two cases were another resident and worker at a coronavirus-stricken aged care facility, Arcare Maidstone nursing home, in Melbourne’s northwest. The cases were reported on Sunday afternoon.
The fully vaccinated 79-year-old resident lives close to a 99-year-old woman and 89-year-old man who have previously returned positive tests.
Despite remaining asymptomatic, the resident will be taken to hospital.
The other case is a registered nurse who worked at the aged care facility on Saturday, is also asymptomatic and has received a first COVID-19 shot.
Melbourne is in its second week of strict lockdown and Health Minister Martin Foley has remained non-committal about guaranteeing restrictions will ease come June 10.
There are now 390 sites where exposure to the virus may have occurred and they can be viewed at coronavirus.vic.gov.au/exposure-sites.
The Victorian vaccine rollout is ramping up with the state to receive an extra 100,000 Pfizer doses from mid-June.
Paramedics will be the next frontline group to be prioritised for vaccination from June 9.