Returned travellers caused '99 per cent' of second wave

More than 99 per cent of Victoria’s second wave of coronavirus can be linked to returned travellers, genomic sequencing shows.

A director at the Doherty Institute, Ben Howden, told the inquiry into the state's hotel quarantine program on Monday that, from the start of June, three strains of COVID-19 had been detected, each imported from overseas by at least three separate returning travellers.

Over that period, all returned travellers were required to stay in hotel quarantine.

"What I could say, a high-level statement would be, that over 99 per cent of all current cases in Victoria for which we have genome sequences, are derived from [those three sequences]," Professor Howden said.

"Such that essentially all current cases, bar a few, are from those [three sequences]."

But Professor Howden would not say definitively that the second wave was linked to hotel quarantine because he did not have the additional epidemiological data.

That data was expected to be explored during Tuesday's hearings.

Professor Howden said it was "very unlikely" any strains of coronavirus active in Victoria could not be linked to the clusters that started with returned travellers.

"A number of apparent travel associated cases at the start of the cluster and then a dominance of apparently locally acquired cases after that," he said.

Professor Howden, head of genomic sequencing at the Doherty Institute, said Institute’s genomic sequencing looked at 46 per cent of all the state’s cases up to July 23.

That sample provided a sufficient cross-section to be confident that all of Victoria’s current second wave was linked to returned travellers, he said.

"I believe the majority of cases that are yet to be sequenced fit within those clusters, but we can’t be definitive on that until the sequencing is complete," Professor Howden said.

He confirmed their data showed the strains of COVID-19 from Victoria’s first wave had died out by late May and early June, when the second wave began to spread.

"What we have done today, more than 99 per cent fit within those clusters we discussed … I doubt that proportion will change much but as we go along in time, there is a possibility that a new cluster could be introduced through another mechanism and we may detect that.

"But for the current situation, it is very unlikely that we will be detecting many samples that fall outside these clusters."

Chief Health Officer Brett Sutton and Premier Daniel Andrews had previously said "at least a significant portion" of Victoria’s second wave was due to hotel quarantine breaches.

As of July 29, 65 genomic clusters were identified, Professor Howden said in his statement.

These clusters ranged in size from two cases to more than 1000 cases.

Hotel inquiry legal line-up

• Tony Neal, QC, the lead lawyer acting for the inquiry, also known as the counsel assisting
• Claire Harris, QC, for the Department of Health and Human Services
• Helen Tiplady, representing the Department of Justice and Community Safety
• Richard Attiwill, QC, representing the Department of Premier and Cabinet
• Andrew Woods, representing Rydges Hotels Limited
• Stephen Palmer, representing the Melbourne Hotel Group
• Julie Condon, QC, representing the Department of Jobs, Precincts and Regions
• Arthur Moses, SC, representing Unified Security

Earlier, the inquiry heard that security guards in Melbourne's quarantine hotels were given inappropriate advice where they were told there was no need to wear personal protective equipment when taking guests out for fresh air or delivering UberEats orders to their rooms.

Infectious disease expert Professor Lindsay Grayson was asked about the Department of Health and Human Services advice to security guards that there was no need to wear protective equipment on the hotel quarantine floor when guests arrived, or during doorway visits if physical distancing could be maintained.

"You would regard that to be inappropriate advice?" asked Arthur Moses, QC, who is representing Unified Security, one of three companies contracted to Victoria's quarantine hotels.

"Yes, I do," Professor Grayson replied.

He was also asked about Australian government training modules provided to security guards which he said should not have been used for that purpose.

Professor Grayson said the document was "completely inaccurate" for quarantine staff.

"I think clearly this is misleading for healthcare workers or quarantine staff if they thought they didn't need to wear a mask, when I would consider it crucial if they were in likely contact with a potentially infectious patient," he said.

"It was the complete opposite of what we teach regarding PPE."

Professor Grayson said anyone working in a quarantine setting should wear full PPE at all times, even for simple tasks including removing a meal tray or escorting someone outside.

"Whether it is in a hotel or anywhere else, the principles are meant to be the same," he said.

Mr Neal noted that thousands of workers at Victoria's quarantine hotels did not become infected with COVID-19, despite crucial failures at Rydges on Swanston and Stamford Plaza.

But he said that meant the program ultimately failed.

"If the intent of the program was to prevent travellers from infecting other people with COVID-19, then to that extent it fell short of its goal," Mr Neal said.

So far COVID-19 has killed 334 people in Victoria and on Monday the state confirmed 282 new cases and 25 deaths in the previous 24 hours – a record number of fatalities for a single day.

Mr Neal confirmed government ministers would be called to give evidence before the inquiry delivers its findings on November 6.

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