Experts continue to warn of the dangers of Australia's current hotel quarantine system, with one believing the program could still be in use in 2023.
With the virus mutations wreaking havoc in other parts of the world, notably in India where daily cases have now surpassed 350,000, and Australia's slow vaccine rollout, there are fears our borders will remain closed for the foreseeable future, likely to a select number of nations or potentially the rest of the world.
"Given the high number of cases globally and the slow rollout of vaccines in most countries, Australia will need supervised quarantine for some time to come, most likely until 2023," Professor Michael Toole, an epidemiologist from the Burnet Institute, explained for The Conversation.
Epidemiologist Professor Raina MacIntyre, Head of the Biosecurity Program at UNSW's Kirby Institute, says the hope is borders can be opened once everyone is vaccinated, yet there are three major problems that could delay the process.
She told Yahoo News Australia the speed of the vaccine rollout, the vaccines' efficacy and the emergence of vaccine-resistant mutations pose potential threats to open borders, widely suggested to likely happen in early 2022.
"The speed of vaccination is very slow, with supplies limited while the efficacy of the vaccines being used need to be high enough,' Prof MacIntyre said.
"Variants of concern may also arise which are resistant to vaccines – for example, the AstraZeneca vaccine has 0-10 per cent efficacy against the South African variant."
In a recent paper, Prof MacIntyre noted if vaccines have a efficacy of less than 70 per cent, herd immunity cannot be achieved and Australians will be at risk of potential outbreaks.
Australia remains 'vulnerable'
Dr Zoe Hyde, an epidemiologist at the University of Western Australia, reiterated the virus can still be transmitted among those who have received the jab, meaning border measures will continue to play an important role for the nation.
"Australia will be vulnerable until we've achieved herd immunity. We must keep quarantine to protect us until then," she said on Twitter.
The federal government continues to stress the vaccine will have been offered to every adult Australian by October, yet there are mounting concerns that target is unachievable due to the slow administration and uptake of the vaccine.
Hotel quarantine therefore remains Australia's first line of defence for the foreseeable future, which has prompted mounting calls for urgent changes in the wake of recent transmission events inside facilities.
On Saturday WA Premier Mark McGowan confirmed yet another quarantine leak had occurred when a hotel staff member became infected before passing it on to two flatmates.
Mr McGowan said there is "no explanation" as to how the worker became infected, raising further questions over the suitability of hotels as quarantine facilities, particularly surrounding inadequate ventilation.
Mr McGowan has repeatedly called on the federal government to reevaluate the system and to use custom-built facilities instead, such as Christmas Island Detention Centre – a call also made by Queensland Premier Annastacia Palaszczuk.
Quarantine problems reoccurring 'like a broken record'
Prof MacIntyre said it was time the Infection Control Expert Group (ICEG) recognised airborne transmission was playing a major role in the transmission of the virus inside facilities.
"The virus is airborne, and ventilation is key," she told Yahoo News Australia.
"We need formal recognition of airborne transmission, and thereby attention paid to ventilation and respiratory PPE.
"As long as airborne transmission is denied, we cannot fix what is wrong with HQ, and we will keep replaying the story like a broken record."
Prof MacIntyre said there had even been evidence of floor to floor transmission through faecal aerosols travelling up the sewage pipes.
"In one case virus was identified all over the bathroom on the floor and apartment directly above the infected apartment – and that apartment was vacant," she said.
She added buildings built before 2016 may not meet ventilation requirements and are at risk of accumulating aerosols.
Despite being more costly, she said it was vital air inside is not recirculated.
The Morrison government has been defiant in recent weeks amid calls for changes to the program.
"Hotels are working very well," Defence Minister Peter Dutton told Channel Nine's Today show on Friday.
However Health Minister Greg Hunt appeared open to proposals of a custom-built, 500-bed centre on Melbourne's northern fringe. It would come at a cost of $200 million for the federal government.
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