The fall of Omicron: Experts predict how the latest wave will end

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Here we are again. Exhausted and holding our collective breath, in the midst of another wave of coronavirus. Only this time, the outbreak is growing by tens of thousands of new cases every day.

There are potentially hundreds of thousands more cases we do not even know about, as testing systems buckle under pressure, hospitals and emergency departments start to burst at the seams and ambulance services are pushed to the brink.

The rise of Omicron in Australia has been swift and staggering, plunging our weary beings into yet another apocalyptic existence.Credit:James Brickwood

The rise of the Omicron variant of coronavirus has been swift and staggering. So, how will this chapter of the pandemic end in Australia?

There is a cautiously optimistic view among some infectious diseases experts that the rapid surge of Omicron infections in Australia will be measured in weeks rather than months, particularly in Victoria and NSW, where it will peak before the end of January.

Some predict a rapid explosion of infections followed by a swift, sharp decline that has been described in South Africa as “more of a flash flood than a wave.”

“The cases are going to rise very, very rapidly and they are going to decline very, very quickly,” James McCaw, an epidemiologist and mathematical biologist with the University of Melbourne, who did modelling on Omicron for the federal government, said.

“The reason for this is that the virus spreads to so many people that people who are infected do not meet susceptible people before they recover. And, so the virus starts to go away again.”

University of Sydney infectious diseases expert Robert Booy also forecast the Omicron wave would soar and fall at breakneck speed.

“The light that burns twice as bright, burns half as long,” he said. “In short it’s going to come fast, and it’s going to leave fast.”

Burnet Institute director Brendan Crabb says governments should be planning for a permanent pandemic.Credit:Burnet Institute

But Omicron’s presence serves as an ominous warning about what will continue to happen unless we start to get serious about the endgame, according to the head of the Burnett Institute Brendan Crabb.

“Omicron is going to come and go quickly, very quickly. This is not a good thing,” the microbiologist said. “Speed means more people get it, speed means it’s harder to treat those people who get it and [speed means] struggling healthcare systems.”

Professor Booy said the greatest failure of governments in Australia was that they had been reactive and delayed imposing restrictions when Omicron emerged, lagging behind on face masks and density limits while a testing crisis continued.

He said two years into a pandemic it was not acceptable that authorities were not planning for a permanent pandemic.

“We’re living in reactive times when we need governments to be proactive,” he said. “We got so centred on vaccines, we forgot the basics: strong test, trace, isolate, quarantine and social distancing systems.”

Kirby Institute virologist Associate Professor Stuart Turville remains unconvinced the Omicron variant will simply burn out and disappear.

He points out that unlike Australia, which has arguably controlled spread of the disease until now, the population in South Africa had higher levels of natural immunity.

While vaccination rates remain low in South Africa, hovering at about 30 per cent, many were infected by several variants before Omicron, including the vaccine-evasive Beta variant which afforded them a layer of natural immunity that does not exist in Australia.

Other more vaccinated countries, like the United Kingdom and the United States where Omicron is spreading like wildfire, have endured more deadly coronavirus waves than Australia, also have greater protection through the phenomenon known as convalescent immunity.

“The thing about Australia is that until now our immunity has been primarily driven by vaccination,” Professor Turville said. “So, the world will get very interesting data sets from Australia about what Omicron does to people who are double-dose vaccinated, but have never been infected with the virus.

“We are likely to have a very unique experience globally and an immune response here that has not been seen before. I think it’s almost impossible to predict how this will play out.”

Professor Turville believes while Australia’s planned easing of restrictions could probably have kept Delta at bay, the plans vastly underestimated Omicron, leaving millions scrambling for rapid antigen tests and governments with no clear indication of where or how the virus was spreading.

“Unfortunately, when this thing hit in late November the structures that we had in place were not fluid or nimble enough to pivot as fast as the virus does,” he said.

“We were making a lot of decisions about opening up before we knew what it was up to. We knew Delta better than we did Omicron. We planned for doing things with one variant. But the virus had other ideas.”

He said Omicron was already flying by the time we knew what it was up to, hidden behind its predecessor Delta. Omicron continues to replicate and mutate at high-speed.

“Omicron is doing things right now that we don’t know about,” he said.

Professor McCaw predicted this week that Victoria will hit the peak of its Omicron outbreak before the end of this month, ahead of a record wave of hospitalisations predicted in late January or early February.

Cases numbers could get up to the high tens of thousands, he said, but the true number will be “five to ten times higher” than officially reported, reaching hundreds of thousands of active cases on any given day.

Some infectious disease experts predict anywhere between 70 and 50 per cent of the population in Victoria and NSW could will soon be exposed to or infected with coronavirus.

Experts The Age spoke to were unanimous in their view that the sheer numbers of infections alone would trigger an exponential rise in hospitalisations, most of which may not end up on ventilators in intensive care, but would still be seriously ill enough to require medical treatment or a shorter hospital stay.

Even if one per cent of Victoria’s almost 22,000 new coronavirus infections required hospitalisation, that could still equate to roughly 220 people needing urgent medical care each day.

Booster shots will be crucial, Professor Booy said, with early indications a third dose can halt transmission and provide optimum protection against omicron.

So, what about Delta? Omicron appears to have outrun Delta in Australia for now, but Professor Booy points out that with the exception of Africa, all continents continue to fight both variants.

”Omicron and Delta are both still causing trouble across the world,” he said. “We have plenty of Delta circulating at the moment and we’ve got the enormous risk that we’ll find yet another virus that transmits even better than Omicron.“

Despite this, Professor Booy is optimistic that while Omicron is not the end of the pandemic, it’s a big step towards something resembling post-pandemic life.

“There’ll be more variants into the future and they will have different transmission properties,” he said. “There is no end of COVID, it will just change, and will slowly become less and less of an acute issue.”

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