Baffling stats (and many conflicting ones) abound when it comes to this virus.
It was always known that what would ultimately transpire would only be observable ex-post facto
Especially in relation to the two most determining variables, namely:
1. The actual infection rate, and
2. The mortality rate.
And not just in raw aggregate terms, but in terms of distribution across demographic groupings.
The first variable, how infectious this virus is, will remain indeterminate (since we don't know what we didn't know in terms of what the number of undiagnosed cases was at each point of the testing timeline). But I have to say, for a country with a lockdown that started quite late in the piece and which is clearly far from comprehensive [*], that Australia has only had some 6,500 reported cases of this thing (with a maximum number of cases at any one time of less than 5,000 cases) doesn't make too much sense to me.
But the second variable, namely the mortality rate, can be measured with increasing accuracy as the data set becomes larger and more representative over time.
Of the 3,555 closed cases, we have had 61 deaths.
So that equates to a maximum mortality rate of 1.69%.
(Maximum, because there would have been a number of recovery cases that were not reported.)
Now 1.69% as a mortality rate might sound high, but if one looked at the demographic distribution of those deaths, all but one of them occurred in the sub- 60 year old cohort.
So, if we work out the mortality rate of that sub-60 year old part of the population (which is 78% of the population, i.e., some 19m people) it is derived by dividing the number of deaths by the number of closed cases in that cohort.
I have not found a reliable source that breaks down the closed cases by age category (but the government does provide the number of reported cases per age group), so one approach is to use the proportion of reported cases per age group as a proxy for the proportion of closed cases in each age group.... recognising, of course, that the number of unreported per capita recoveries will be a lot higher in the younger ages than in the over-60s.
So using number of cases in age age group as a proxy for closed cases for each age group appears to be reasonable and, if anything, conservative approach.
According to the Department of Health, around 70% of the cases reported occurred in the sub-60 year old category.
So, applying that 70% fraction to the total number of closed cases, we get an estimate of 70% of 3,555 = ~2,500 of recoveries in the sub-60 age category.
So that works out to a mortality rate of 1 divided by 2,500, i.e., 0.04% in the sub-60 year age cohort.
(And again, that's the maximum mortality rate because it is based on only recorded recovery cases, and not recovery cases which are not observable.)
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In that context, it will seem increasingly incongruent to keep the entire country in wholesale lockdown, at the cost of hundreds of billions of dollars of economic contraction and the attendant loss of livelihoods and all the multitude of social ills that accompany that.
I strongly suspect that before long, a moderated lockdown strategy will need to be adopted - broadly along the lines of keeping the most vulnerable citizens (plus-70 year olds) in lockdown - but freeing the bulk of the population to continue with their jobs and livelihoods.
Using a sledgehammer to crack an egg might have been fine at the outset when we didn't know what we were dealing with, but now the real-time data provides some critical insights which suggests to this observer that the universal and indiscriminate lockdown approach has served its purpose and that a more targeted approach is going to be required before long.
[*] Heck, a little more than a month ago, we were boasting about fitting a record number of people into the MCC for a cricket match!
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