Without serious action, Australia may run out of intensive care beds by early April

By Megan Higgie and Andrew Kahn

Updated 19 March with predictions for Australia (which is now one day sooner) and adding a prediction for NSW.

Before reading further…

1 | ICU beds are the difference between surviving and dying from COVID-19

Below are the number of ICU beds, both in public and private hospitals, in Australia (by state) and NZ, from the last CORE Report of the Australian and New Zealand Intensive Care Society (ANZICS) [note 2]:

Figure 1. Number of ICU beds in Australian and New Zealand public and private hospitals as of 2018 [2].

2 | Number of COVID-19 cases before we run out of ICU beds

Table 1. Intensive Care Unit (ICU) beds in Australia (overall and by state) and New Zealand, and the number of COVID-19 cases before these ICU beds are full. Based on data from [1] and [2].

3 | What date will we run out of ICU beds?

Next we can use some mathematical modelling to estimate what date we will run out of ICU beds.

We can only use this modelling where there is enough cases to fit a model. Currently that is Australia as a whole and now NSW. As cases accumulate we will add this analysis for other Australian states and for NZ. See note [3] for details of our analyses.

3.1 | Australia

With the current worst-case scenario of exponential growth of COVID-19 cases, Australia may run out of ICU beds between 7 and 9 April

Figure 2. With the current worst-case scenario of exponential growth of COVID-19 cases, Australia may run out of ICU beds between 7 and 9 April. The black line is the exponential growth curve of COVID-19 cases, using the 10 days of data since Australia reached over 100 cases (black dots). The blue shading is the 95% prediction intervals. The red line is when Australia reaches the ICU bed limit based on 5% of cases requiring ICU.

3.2 | NSW

With the current worst-case scenario of exponential growth of COVID-19 cases, NSW may run out of ICU beds between 5 and 9 April

Figure 3. With the current worst-case scenario of exponential growth of COVID-19 cases, New South Wales (NSW) may run out of ICU beds between 5 and 9 April. The black line is the exponential growth curve of COVID-19 cases, using the 6 days of data since NSW reached over 100 cases (black dots). The blue shading is the 95% prediction intervals. The red line is when NSW reaches the ICU bed limit based on 5% of cases requiring ICU.

Assumptions

  1. That all ICU beds are only used by COVID-19 patients and not for any other medical emergency (e.g., car accidents, cardiac arrests) — this assumption is plainly not correct, so our actual date will be sooner than predicted.
  2. That Australia and New Zealand have not added any new ICU beds since the 2018 ANZICs report. This is not correct, but we could assume that at least those new ICU beds added in 2019 are full due to the non-COVID-19 critical cases.
  3. That ‘only’ 5% of cases become critical. We have seen anecdotal reports of 6–10% of people requiring ICU beds. Obviously this would bring the actual date much sooner. We have also seen reports that it may be less than 5%. But while we still have exponential growth of cases then halving and quartering this 5% rate only extends the estimate on when we run out of ICU beds by days – not by months.
  4. That the current strategies to control the spread of COVID-19 remain the same (e.g., schools, universities, daycares, and non-critical businesses and services remain open). When we first published this article this was still true. Since then some stronger measures of social distancing have been introduced. Whether the effects of these measures will be strong enough to halt the exponential growth of cases will only been seen in the data a week or so after people begin adhering to them.
  5. That we are confirming all cases that are occurring. With the criteria for testing remaining being quite limited in Australia then we are missing cases. This brings the actual date sooner than what we are predicting here.
  6. That there is no capacity to easily increase the number of ICU beds rapidly and massively. There are some reports that makeshift ICU beds can be made, but how many and how quickly? Both unknowns at this stage.

What else do we need to know?

  1. That there is a large lag between becoming infected and being ill enough to require medical attention. This lag is on average 10–14 days [note 1]. Given that 7 April is 19 days away, we only have 5–9 days to take the serious action necessary to prevent this human disaster in Australia, and less time in NSW.
  2. The majority of infections are passed on before someone even shows symptoms. Approximately 80% of infections occur when an infected person does not even know they are infected [note 4]. This is a much under-appreciated fact and explains why Australia is still experiencing exponential growth in spite of quarantining people once they are sick — they have already infected people before they went into quarantine!

What do we need to do to prevent unnecessary deaths from 7–9 April onwards (both individually and as leaders)?

The only effective measure is that we go into lock-down and practice extremely strong social distancing within the next 5–9 days.

If people cannot tell when they are sick and pass on the majority of infections before their first symptoms show, the only possible course of action is to avoid contact with other people.

There is strong evidence [note 5] to show that only the action of extremely strong social distancing (also known as ‘suppression’) has been the difference between the high death rate in Italy versus the much lower death rates in China (especially once they knew what they were dealing with), Taiwan, South Korea, and Japan.

Yes, this may mean schools and daycares closed (except for children of critical workers, such as medical people and absolute core infrastructure needs such as sewerage plants, etc.), it means most businesses closed. Yes, businesses and we as individuals will lose money, but we are going to lose money either way and much much more than money if we don’t act soon and effectively.

The benefits of this early and strong action will be multifold:

  • we won’t lose a massive number of our family, friends, and colleagues (due to lack of ICU beds — see above analysis)
  • the actual number of infections will be lower and so we will reach the peak number of cases per day sooner (because the daily number of infections starts to decline, and eventually we will have less cases one day than the day before — that is, we have passed the peak). This means the sooner we act, the sooner that we can relax the strong social distancing.
  • it buys us time — time to find a vaccine, time to increase ICU bed capacity and train staff, time to make more protective equipment like masks. See an excellent article on why we need time here https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56.

Notes

  1. ANZICS Centre for Outcome and Resource Evaluation 2018 Report, page 7
  2. Based on data from Juliette O’Brien at https://www.covid19data.com.au/, we fitted an exponential model of confirmed cases over time since 10 March for Australia (the date Australia recorded its 100th confirmed case) and 14 March for NSW (the data NSW recorded its 100th confirmed case).
  3. Li et al. 2020. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV2). Science
  4. Ferguson et al. 2020. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID19 mortality and healthcare demand

Lecturer in Genetics, Evolution, and Statistics at James Cook University, Australia.

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