Covid-19 Blog Series #4

What comes next?

Australia’s mortality rate for Covid-19 remains very low, although it’s getting closer to the expected figure of around 1.5%. Currently, based on Department of Health figures, it’s just under 1% but has been growing recently [1]. We can expect this growth as the peak of infections about 3 weeks ago will be resulting in deaths now.



It is possible that the death rate in Australia will be lower than in other parts of the world as it hit Australia in warmer weather and our health system is among the best in the world. At no time was the Australian system overwhelmed as has been the case in some countries.

Another interesting outcome in Australia is that we appear to have, near as dammit, identified all cases. Testing capacity, one area where we were overwhelmed early, is now being relaxed nationwide, with the new criteria being simply: if you have symptoms, you will be tested. This despite Australia being one of the most tested nations in the world [2].

While this is a remarkably good outcome for Australia, it does suggest that the rate of infection is multiples higher in most parts of the developed world. In the USA for example, there have been 12,868 deaths. At a CFR of 2.0%, this would imply a total number of infected 1.4 million, meaning there would be about 800,000 unidentified cases. At a CFR of 1%, there would be over 2 million unidentified cases.

Globally, this means that the best case scenario is that there are 4.6 million unidentified cases in the world with potentially up to 11.5 million. In short, while Australia's position may be good, there is no early prospect of the disease being contained in other parts of the world.

Australia's Options are Limited

This places Australia in a tricky position. There seems to be no good reason why we can’t relax the lockdown measures, but we would still face the danger of the disease being reintroduced by foreign travel. This will continue to be the case until we either develop a vaccine or we develop a level of herd immunity.

To illustrate, if we continue as we are, we can reasonably expect the disease to peter out entirely in Australia in the next few weeks, however it will still be virulent in Europe and the USA. It will probably be virulent in Africa and India but data from those locations is not great. So at this point, does Australia reopen for business but keep its borders closed?

Even with closed borders, the likelihood of the disease being reintroduced is fairly high. Whether through cargo, diplomatic travellers, humanitarian means or otherwise, our borders will still see some seepage.

The best approach at this stage appears to be a reopening of the country with a continued lockdown for the most vulnerable; the elderly and infirm, those with pre-existing immune or respiratory conditions and anyone called Karen.







[1] All figures as at 16 April 2020.
[2] By rate of testing, Australia has dropped back a little from some of the world leaders (eg Germany, Italy, UAE). Mainly this is due to concerted global efforts in badly effected countries (Italy) and partly because we haven’t ramped up testing capacity further. Our testing rate among comparable countries (say population > 10,000,000) is about 4th or 5th highest in the world.

Images
Photo: Novel Coronavirus SARS-CoV-2
This transmission electron microscope image shows SARS-CoV-2—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S. Virus particles are shown emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like. Credit: NIAID-RML, available at https://www.flickr.com/photos/niaid/49534865371
Tables: own work