That modelling bears out what politicians, health authorities and emergency doctors have been saying: the state is well-equipped to cope with an increase in infections.
But it also underscores another message: the need to slow the pandemic’s growth, and soon. Only 10 days ago Victoria’s daily infection rate was just 134.
The state has 695 intensive care beds and the capacity to rapidly expand that number if cases surge, according to state Health Minister Jenny Mikakos.
William Mackey, the Grattan Institute senior associate who did the modelling, said: “From where we are now, and the lockdown steps taken, things would have to go seriously wrong for ICU capacity to be an issue in Victoria.”
How close a healthcare system is to capacity is an important figure because it directly relates to mortality.
High-income countries with excellent healthcare systems, like Italy, suffered high mortality rates after their hospitals became overwhelmed.
Australian hospitals have not been overwhelmed, meaning local COVID-19 patients have, so far, enjoyed world-leading survival rates.
What is Victoria’s surge capacity?
The state government has more than 1000 ventilators ready to set up in new intensive care beds as part of its plan to activate surge capacity if COVID-19 infection numbers soar, with thousands more on order.
Australian College of Critical Care Nurses chief executive Rand Butcher said health authorities had spent months working to boost surge capacity, which required physical beds, ventilators, monitoring equipment and specially-trained nurses, along with ICU drugs and personal protective equipment.
The federal government has amassed 7500 ventilators, 220 million masks and reserves of intensive care drugs in the national medical stockpile and has trained up 15,807 nurses to work in intensive care, including 5619 in Victoria. The state government has separately trained an additional 1629 ICU nurses.
Mr Butcher said the extra Victorian nurses trained through the program could staff 1445 intensive care beds under current clinical standards, which allocate one nurse to every patient, with about five nurses staffing each bed on a seven-day roster.
The Grattan modelling showed that it would take between 4000 and 7700 daily new infections over 10 days for this capacity to be reached, a scenario that would require “a lot to go wrong” given current infection rates and the stage three lockdown brought in two weeks ago.
About 1800 doctors would be needed to staff intensive care beds under the surge plan and Australian and New Zealand Intensive Care Society president Dr Anthony Holley said hospitals would have their pick of “highly skilled” anaesthetists and other physicians freed up by the elective-surgery freeze.
How the modelling was done
To estimate whether hospitals could be overwhelmed, modellers asked two key questions: For every 100 people who get COVID-19, how many will end up in ICU? And how long will they stay there?
The Grattan Institute model assumes that, in a best-case scenario, two people in every 100 will need intensive care – four in the worst-case scenario.
In the later scenario, 910 new cases a day over 10 days would fill the state’s existing non-surge intensive-care capacity.
Intensive care admissions tend to lag confirmed cases by a few weeks as patients get progressively sicker, Cabrini Health deputy director of intensive care Associate Professor David Brewster said.
The Grattan model assumes patients stay in intensive care for 10 days, reflecting the average stint for the first wave of severely ill coronavirus patients in Australia in March.
The model assumes 50 per cent of Victoria’s 695 ICU beds could be made available for COVID-19 patients, in line with official federal government models. It does not model surge capacity.
Victoria’s ICU beds were 85 per cent full last Thursday, with 380 out of 446 staffed beds full. At the time, there were 40 COVID-19 patients in hospital, including nine in intensive care.
On Friday, eight days later, 122 COVID-19 patients were in hospital with 31 in intensive care.
Austin Hospital director of intensive care Dr Stephen Warrillow said intensive care units were designed to run near capacity, but that capacity could be quickly increased.
“We don’t have a bunch of resources sitting there chronically underutilised – because that’s not efficient. The system has the capacity to flex to meet demand.
“If I need to double my ICU capacity tomorrow, I make several calls. And we convert it. And that happens in about a day.”
Chair of epidemiology at Deakin University Professor Catherine Bennett suggested the Grattan Institute calculations may be a little conservative, but were generally similar to her own. “We have plenty of capacity, even before we move into surge capacity.”
Professor Tony Blakely, a leading epidemiologist based at the University of Melbourne, argued improving treatments likely would push the estimate of how many people ended up in intensive care down.
“We have ample ICU capacity for the current case loads. No panic, please,” he said.
How high will Victoria’s infection rate get?
Victoria’s daily number of new infections has jumped from 73 at the start of July to 428 on Friday.
However, Chief Health Officer Professor Brett Sutton told media he was confident the virus was under control.
“We have significant controls in place. We have the kind of restrictions that worked through our first wave. I expect them to work through this wave.”
Epidemiologists look at the effective reproduction number – an estimate of how many people each infected person spreads the virus to – to estimate how an epidemic is tracking.
If the number is one, the epidemic will plateau. If it falls below one, it will slowly shrink.
Professor Sutton said Victoria’s reproduction number was “coming down close to one”.
Liam is The Age and Sydney Morning Herald’s science reporter
Dana is health and industrial relations reporter for The Sydney Morning Herald and The Age.
Aisha Dow reports on health for The Age and is a former city reporter.