Victorian authorities have warned residents that although lockdown restrictions are easing, they are no closer to pinpointing the source of the Delta virus strain spreading in the community.
Last week, health experts revealed there was a second virus strain affecting two Melbourne families that wasn’t related to the original Whittlesea outbreak.
Genomic sequencing showed the case was from a man in hotel quarantine, but how the virus spread to two Melbourne families who never came into contact with him is still a mystery.
On Thursday, Deputy Chief Health Officer Professor Allen Cheng told media that all four working theories on how the families had contracted the virus had been disproved.
“We’re not coming up with a transmission path between this case in hotel quarantine and either of the families,” Cheng said.
“So while it’s the judgement of the public health team that we are in a position to ease restrictions we are by no means out of the woods yet.”
It’s part of the reason authorities are requiring citizens to continue wearing masks in outdoor settings, which is a slight change to the original road map out of lockdown.
Cheng said there are four working theories for how the virus went from a hotel room to two unrelated families.
- It spread while the infected man was on a plane.
- It spread after the infected man left hotel quarantine.
- It spread to another hotel resident who then went out into the community.
- It spread to a hotel quarantine staff member who then went out into the community.
However, at every turn authorities have been thwarted.
They reviewed test results from all 24 plane passengers and also the flight crew, and concluded it wasn’t possible that the Delta strain had spread there.
Theory number two is also “unlikely” according to Cheng “as he (the infected man) had been correctly cleared with positive serology” before he was allowed to leave quarantine.
Tests on the man’s housemates also showed that he was in no ways contagious after leaving the hotel.
Residents at the hotel also tested negative.
“We’ve recontacted the 12 (hotel) residents and tested most of them again, but noting that they’d all tested negative multiple times while in hotel quarantine and in most cases had also been tested after their hotel quarantine period,” Cheng added.
The only remaining possibility is that the Delta strain spread through a hotel staff member.
“We’ve cross-checked 268 staff at the Ibis and about 370 at the Holiday Inn, including health care workers, cleaners, hotel staf, VicPol, CQV and contractors who entered the hotel and we’ve ensured that they’ve all had their surveillance tests and they’re all negative,” Cheng said.
He pointed out that they were still “waiting for a tests to come back” but he wasn’t holding out hope.
B1.617.2, or the Delta variant, is the COVID strain most common in India, and is thought to be 50 per cent more transmissible than the UK strain.
The Kappa strain is another Indian variant that was linked to other cases in the Melbourne outbreak, which originated from a South Australian person in hotel quarantine.