Covid-127

Dan O'Heirity

Covid-19 Facts and Figures from Victoria, Australia

The state of Victoria has two roadmaps to take us out of the current lockdown measures. There is one for metropolitan Melbourne and one for regional Victoria. Before we take a look at these road maps, I want to provide current data for Covid-19 cases in Victoria. According to live data from the Victorian government, as of today 17th September, we have seen 19,943 total cases of Covid-19 in Victoria. There have been 42 new cases in the last 24 hours. 18,513 people have recovered from the virus and there are 991 active cases. A total of 737 people have died from Covid-19 with 8 new fatalities in the last 24 hours giving a fatality rate of 3.69%. This figure is very close to the current figure for the fatality rate worldwide which according to a live data source is 4%. 107 people are in hospital and 11 people are in intensive care units. To put Victoria’s figures in the context of Australia as a whole, live data from the Australian government reports that there have been 26,779 confirmed Covid-19 cases in Australia. 23,721 people have recovered with a total of 824 deaths giving a fatality rate of 3.47%. These figures mean that 74.47% of all cases of Covid-19 in Australia, have been cases in Victoria. 89.44% of all deaths in Australia have been in the state of Victoria.

Victoria Has Two Roadmaps to Move Towards “Covid-19 Normal”

The roadmap for metropolitan Melbourne will see extreme lockdown measures continuing for weeks to come. A curfew is in place between 9 PM and 5 AM. We have to remain within 5 KM of our homes except in exceptional circumstances. A maximum of two people can meet together for exercise or for recreational purposes. A “single person bubble” is in place with 1 nominated visitor allowed for people living alone and for single parents. Easing of lockdown measures will be instituted after October 26th, 2020 as long as the daily average number of cases in the previous 14 days is less than 5 (state-wide) and as long as there have been less than 5 cases with an unknown source in the previous 14 days (state-wide total).

Key points for this stage are that there will be no restrictions on leaving one’s home and public gatherings of up to 10 people will be allowed. The final stage of easing restrictions will be instituted after 23rd November as long as there have been no new cases in Victoria for 14 days. It is only at this point that hospitality venues will be able to have seated customers and retail outlets will be allowed to open. Metropolitan Melbourne will only return to “Covid-19 normal” when when there have been no new cases for 28 days, no active cases (state-wide) and no outbreaks of concern in other States and Territories. Under Covid-19 normal life will, as the designation suggests, pretty much return to normal. For example, no restrictions on leaving one’s home, retail and hospitality open, no limits on weddings and funeral, and all entertainment venues open.

Under the regional Victoria roadmap, regional Victoria is already at the third stage of restrictions being eased because the vast majority of Covid-19 cases have occurred in metropolitan Melbourne. There are no restrictions on leaving home. Public gatherings of up to 10 people are permitted. Visitors allowed at other homes from 1 other household up to a maximum of 5 people. Schools will return to onsite learning at the start of the next term with safety measures being put in place. Hospitality venues are open for takeaway services. All retail outlets have been allowed to open albeit with density restrictions and safety measures in place. The current difference between metropolitan Melbourne and regional Victoria is acute, something that I feel everyday as the majority of my staff work at a campus in regional Victoria.

Regional Victoria will further ease restrictions on 23rd November as long as there have been no new cases across Victoria for 14 days. At that time there will be no restrictions on leaving one’s home, public gathers of up to 50 people will be allowed outdoors, 20 visitors will be allowed to be in a home at any one time, hospitality venues will be open for seated service, all retail will be open and entertainment venues will be opened with some restrictions. Regional Victoria will move to “Covid-19 normal” when there are no new cases for 28 days and no active cases (state-wide) and when there have been no outbreaks of concern in other States and Territories. Life under Covid-19 normal for regional Victoria will be exactly the same as life under Covid-19 normal in metropolitan Melbourne.

Beware Armchair Analysts Who May Lead You Astray

The obvious question to ask now has to do with whether these roadmaps to recovery are justified in terms of the data and the modelling that is available for Covid-19. A story from ABC news reports on data modelling from the University of Melbourne and New England which shows that the extreme lock down measures imposed on metropolitan Melbourne are absolutely necessary. The heart of the argument is that under Stage 3 restrictions, the growth of the virus was slowed to the point where cases were taking 49 days to halve in numbers. Stage 4 restrictions have led to cases halving in numbers every 18 days giving a rate that is twice as fast as that under Stage 3 restrictions. I would have to say that the ABC news story is not entirely clear on just what the growth rate means. However, there is a simple explanation of the growth rate from a different ABC News story.

Basically, the growth rate is calculated by taking today’s new reported cases and dividing the figure by yesterday’s new cases. However, Covid-19 figures are volatile and so the growth rate tends to be calculated over a longer period of time e.g. comparing this week’s figures with last week’s figures. If the growth rate is above 1 then the number of new daily/weekly figures is going up. If the figure is below 1, the number of new daily/weekly figures is going down. For those of you who are mathematically inclined, there is a more in depth mathematical explanation of what “growth rate over time” means at this maths website. The other main argument in the ABC News story is that the Stage 4 restrictions must be kept in place in metropolitan Melbourne to avoid a resurgence of the virus.

At this point I would normally query the data to a significant degree but first I want to acknowledge that I am what “The Conversation” has referred to as an “armchair statistician”. In other words I talk about data and statistics even though I have no formal training in data analysis or statistic analysis. The article argues that armchair statisticians make 5 mistakes. I shall highlight some of those mistakes. First, we fail to understand the concept of the Infection Fatality Rate (IFR) which is calculated by dividing the number of COVID-19 deaths by all those infected. The IFR for flu is estimated to be 0.1% whilst the IFR for Covid-19 is estimated to be 0.25%. This means that, “COVID-19 remains more than twice as deadly as the flu.” First, I plead not guilty with respect to this mistake. Secondly, and good God, the IFR for Covid-19 is estimated to be just 0.25% and we’ve shut down Australia and, indeed, the whole world.

Another mistake made by armchair statisticians is to confuse infections with cases. A case occurs when a person is diagnosed with Covid-19. There are many more infections than cases because many people with Covid-19 will never get tested e.g. those with mild or no symptoms. Again, not guilty in this respect as I have made this point on numerous occasions. Furthermore, if there are, for example, hundreds of thousands of undiagnosed cases in Australia then the IFR would be far lower than estimated because the IFR is calculated using the figure for Covid-19 cases. Lastly, deaths should not be compared with cases from the same date range because, to put it bluntly, dying from Covid-19 takes time so deaths from any given time are related to cases diagnosed weeks earlier. Again not guilty.

I’ll Take the Plunge and Say That the Lockdown in Victoria is Not Justified

The previously referenced article from “The Conversation” makes the point that data analysis is incredibly complex and that is really too early in the pandemic to be certain about any of the facts and figures that are being produced. The picture of Covid-19 will, they say, only be known retrospectively. I take their point but at the same time they have rather stabbed themselves in the back by acknowledging that any figures that they produce are only as good as the data that can be collected in the here and now. To put it another, how much stock should we put in their facts and figures? I realize of course that decision makers have no choice but take best advice from epidemiologists and statisticians. After all, governments have to base their decisions on a rational analysis of the situation supported by the best available evidence.

However, I remain unconvinced that the decision to lockdown Victoria was really justified. First, it has been obvious for months now that the Infection Fatality Rate (IFR) has been steadily falling and that it is far lower than we at first thought. Secondly, a very significant number of these cases and deaths have occurred in aged care facilities. According to one estimate from ABC News, there have been 580 coronavirus aged care deaths, mainly in Victoria. Remember that as of today there have only 737 people have died from Covid-19 in Australia. These facts speak to a failure of the Australian government to protect the most vulnerable members of society. The lockdowns should end and those most vulnerable should be protected. However, it is absolutely certain that the Victorian Premier Daniel Andrews will continue to follow the recovery roadmaps that have been laid out.

First Published September 17th, 2020

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