Nearly 500 people in NSW and Victoria are in isolation as health authorities race to find the source of a highly virulent COVID variant that has infected seven people in Melbourne.
Victorian authorities confirmed on Friday that two West Melbourne families had been diagnosed with the Delta variant of COVID, which has been deadly in India and is taking over in Europe.
The transmission link between the two families is thought to be two grade five children who attend North Melbourne Primary School. But the index case in the worrying outbreak is yet to be traced – with Victoria’s chief health officer Brett Sutton saying it is the first time this COVID variant has been detected in Australia outside hotel quarantine.
“It has not been linked to any sequence cases across Australia,” he said.
Professor Sutton said the B1.617.2 (Delta) variant had “very high transmission potential”. While there is little information about the severity of illness it causes, there are anecdotal reports it causes more severe illness in children.
“It is a variant of significant concern,” he said.
NSW Health authorities confirmed late on Friday that the Delta variant was also detected in two community COVID cases in Sydney in May. The origin of those infections has still not been traced.
It is the same variant that the Melbourne families have – although genomic sequencing has shown they have a different strain than the Sydney couple.
The latest cases are also a different variant to that affecting nearly 60 other people infected with COVID across Melbourne, in the outbreak that sparked the Victorian lockdown. They have the Kappa variant, which also originated in India.
Victorian health authorities said on Friday the variant had been identified in a Melbourne family of four who holidayed on the NSW south coast last week – including visiting Gundagai, Goulburn, Jervis Bay, Huskisson and Vincentia.
They have been unable to closely link the cases to other Delta variant cases previously sequenced from hotel quarantine systems across Australia.
This means the source of the family’s infection is unknown.
One of the parents in the family is believed to be the index case in the new outbreak.
About 300 primary close contacts of the family have so far been tested.
The father began to experience symptoms on May 25, a day after the family returned to Melbourne. The whole family subsequently tested positive.
“It is a concern that it’s not linked to other cases but we are chasing down all those primary case contacts for that family and looking into where it might have been acquired,” Professor Sutton said.
“We just have to do what we [have to] do … it is new information, it is an unrelated cluster, it is a variant of significant concern.”
He said the family might have acquired the virus in Jervis Bay, given the approximate six-day incubation period of their virus strain.
But this was not confirmed and Victorian authorities are still investigating.
In NSW, more than 150 people designated as close contacts after the families camping trip are also being tested and are in isolation. NSW had no community cases of coronavirus on Friday.
NSW Health said anyone who has been in any of the listed southern NSW towns should be on the lookout for respiratory symptoms.
Venues of concern include Trapper’s Bakery in Goulburn on the morning of May 24, 5 Little Pigs at Huskisson on the morning of May 21 and the Green Patch campground in Jervis Bay over an extended period.
Anyone who visited those venues at those times must get tested for COVID-19 and self-isolate for 14 days regardless of the result.
Friday’s revelations came as Melburnians entered their second week of lockdown. Earlier hopes that the lockdown might end ahead of time, after revelations of false positive tests, were dashed by the emergence of the Delta cases.
Victorian Acting Premier James Merlino said there were no immediate plans to shorten the lockdown.
“Our answer on that hasn’t changed and nor should it,” Mr Merlino said.