Covid vaccine target: Sydney Uni modelling says 40,000 cases a day if we reopen too fast

Australia’s third wave of Covid-19 infections will peak in early October and could explode to 40,000 a day post-lockdown, new modelling shows.

Australia’s third wave of Covid-19 infections will peak in early October and could explode to 40,000 a day post-lockdown, new modelling shows.

Figures released by The University of Sydney on Thursday found the unvaccinated will make up the bulk of new infections when restrictions are fully lifted.

And it warns the question of whether we have “a soft landing or crash landing” will be determined by hospital preparedness.

Doherty Institute modelling used by the federal government to set the nation’s vaccine targets recommends restrictions be eased once the nation achieves 70-80 per cent vaccination.

At the current vaccination rollout rate, 80 per cent of adults (65 per cent of the total population) are projected to be vaccinated by mid-November, at which point social distancing restrictions are expected to be removed.

But the USYD’s Centre for Complex Systems data found daily Covid-19 case numbers are likely to continue to climb reaching their lockdown peak in early October.

Shoppers wear masks in Ashfield, Sydney. Picture: Getty Images

If restrictions are fully lifted when 80 per cent of adults are vaccinated, infections across Australia may surge to 40,000 per day and exceed half a million cases within a month – even with continued testing, tracing, isolation, quarantine and international travel restrictions.

Professor Mikhail Prokopenko, the centre’s director, said their findings were much “steeper” than those in the Doherty Institute report – and that is a reason to worry.

“In a sense the numbers are of the same order, for example if you look at the total cases the Doherty Institute estimated over 180 days, you do get in the hundreds of thousands of cases, maybe 300,000 to 500,000 cases over six months.

“We say what you will experience is in the order of 500,000 in a month or a month-and-half, it’s much steeper.

“Similarly if you look at the peak of daily cases we say we could approach 40,000 a day by mid-December or end of the year while Doherty say yes, you could approach up to 50,000 a day or 60,000 a day, but at later date – maybe three months. So in that sense they are not unimaginable numbers, it's the steepness that worries me.”

The study, modelled on daily case numbers from July 26 to August 25, found Covid-19 infections are expected to slow from mid-December, with 75 per cent of the population vaccinated and natural immunity developed by three to five per cent of the entire population by the end of the year.

Director of the University of Sydney’s Centre for Complex Systems Professor Mikhail Prokopenko.

Alike the Doherty report, the new modelling also found 80 per cent of infections post-lockdown will be in unvaccinated Australians.

Prof Prokopenko said even if we wait until 90 per cent of the population is vaccinated to reopen, the rise in cases will happen but they “will be simply delayed”.

The clear take away from the findings is that the healthcare system needs to be prepared, he said.

“If we wait till 90 per cent and if that is the limit to the vaccination extent then the rise in cases will be simpy delayed but they will still happen,” Prof Prokopenko said.

“So we are simply saying if we are to open at 80 per cent then we should just brace for this surge and the question of whether there will be a soft landing or crash landing is a question about the preparedness of our health system.

“This will depend on the community continuing its high vaccine uptake, people maintaining social distancing over the coming months, and our healthcare system preparing and bolstering itself to meet the surge of hospitalisations which will come after the lockdown.”

“How is our healthcare system prepared to meet this and deal with that surge?”

Originally published as Covid vaccine target: Sydney Uni modelling says 40,000 cases a day if we reopen too fast