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Victorian lockdown to end 21 October: updated Burnet modelling

Burnet Institute

17 October, 2021

Victorian Premier Dan Andrews announced additional relaxing of the Victorian Roadmap from 21 October when the state is expected to reach 70 per cent double dosed vaccination from COVID-19, five days ahead of schedule.

Premier Andrews said Burnet’s updated modelling predicts cases will now plateau around their current levels before rising, as restrictions are eased, to a daily peak of close to 4000 new cases per day in mid-December. However, hospitalisation rates are now lower, the length of stay is also less.

“We have more case numbers than we would like,” Premier Andrews said. “[But] the acuity of illness is substantially less than we expected. Plus, of course, we’ve reached this 70 per cent rate in record time. Now, single dose is not the same as double, but it does provide a significant degree of protection.”

Along with the faster rates of vaccination levels - Victoria is expected to reach 80 per cent double-dosed around Melbourne Cup time and is pushing towards 90 per cent single dose - these high vaccination levels have enabled the earlier easing of some restrictions and an increase in numbers of visitors to homes, indoor and outdoor hospitality and numbers at public gatherings.

The modelling shows Victoria’s pace and high levels of vaccination has almost-halved the projected number of people expected to die from COVID-19 before the end of the year.

The modelling projects 1212 deaths between July and December 2021 - down from the 2202 projected on 18 September.

The chances of overwhelming the hospital system have dropped from 63 per cent to just 23 per cent.

Modelling conclusions:

  1. Based on the current epidemic growth rate, diagnoses in Melbourne are estimated to reach a peak between 15-27 October.
  2. Easing restrictions is likely to lead to a second peak in infections and diagnoses. Hospital and ICU use may remain relatively flat rather than declining.
  3. Opening fully at 70 per cent vaccination, as opposed to following the roadmap, increases the peaks in diagnoses, hospital demand and ICU demand, and peak demand for hospital and ICU may be required for slightly longer.
  4. Due to uncertainty about whether the epidemic growth rate will be sustained, seasonal impacts and vaccine efficacy parameters against the Delta strain, updated projections are required as more data becomes available.

Victorian Chief Health Officer, Professor Brett Sutton said the Burnet modelling had given them a higher level of optimism moving forward.

“With the very high vaccination coverage, our health system - which will continue to have significant challenges - it will cope,” Professor Sutton said.

Professor Sutton reiterated that earlier Burnet modelling had higher hospitalisation and death estimates because that was the data available at the time, but the speed and uptake of vaccination had surprised many, requiring an update to the modelling.

“We’ve been surprised by the vaccination uptake in Australia, there were those who predicted that we would kind of flatten at the 80 per cent double dose mark. The fact is that we’re getting to 90 per cent with lots of positive indications that it could well be close to 95 per cent. That makes a huge difference. You can’t underestimate what a difference it makes. Between 90 and 95 per cent you are halving the number of completely vulnerable and significantly at-risk individuals. That makes a huge difference to projections for hospitalisation and deaths,” he said.

Updated Burnet Modelling: Victorian Roadmap

NB: Median lines in figures are different to table, because the calendar date of individual simulation peaks are different. This means that the median of [peak values across simulations] is not the same as the peak of [the line generated by plotting the median value at each point]. Figures are for visualisation only, see appendix of Burnet modelling report for additional information.”

Download the modelling

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Burnet Institute

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