Tag: mortality rate

“Current estimates of Covid-19 deaths ‘deeply flawed’ – The Wall Street Journal – Linda van Tilburg”

Let’s just remind ourselves of the current confirmed cases because ultimately the estimated deaths are derived from this data.

Below is an animation of the fatalities over time (you must press play in the bottom left hand corner).

This headline immediately had my attention. Since I made some predictions myself I just had to read what she had to say.

It was coronavirus projections estimating that South Africa could have between 87,900 and 351,000 deaths if the country did not take drastic measures to contain Covid-19 that spurred President Cyril Ramaphosa into action with the 21-day lockdown to enforce social exclusion. These are scary statistics, especially in a country where millions of people have compromised immune systems due to HIV/Aids and TB. Two professors in medicine from the University of Stanford Eran Bendavid and Jay Bhattacharya believe that the World Health Organisation’s 2-4% fatality rate of Covid-19 is “deeply flawed” and that current estimates may be too high. Their argument is based on the fact that it is difficult to determine the number of people who are infected because of “selection bias in testing”. To get a better steer of the hidden cases who are infected by the coronavirus, scientists from King’s College and Guy’s and St Thomas hospital in London are now rolling out Covid-19 symptom trackers where Brits self-report their symptoms to get a steer of the hidden cases – “the iceberg that countries sail into”, which would get policy makers better data to work with. They also believe a “universal quarantine may not be worth the costs it imposes on the economy.” Isolating the vulnerable may be a better option. – Linda van Tilburg

The mortality rate is a very important factor to determine our fate. Italy has, as of writing, a mortality rate of 14.2%, while Germany has a mortality rate of 0.9% (up from 0.3% this time last week). The means, in Italy for the same number of infections, 15.7x more people die. Almost SIXTEEN TIMES more!!!

So what is going on? Before we attempt to answer that, let’s just stress the importance of the mortality rate. If we apply that to the 65% of South Africa’s population I used in yesterday’s post we will have either end up with 331 000 or 5.2 million fatalities. That is a vast difference. Currently, the global average is at 4.5%, which for South Africa corresponds to 1,7 million fatalities.

It must be clear that getting the mortality rate accurate is critical to estimate the scale of the calamity that is awaiting our country.

What are the clues?

Between Germany and Italy lies the USA and the hypothesis that the reason why Germany’s mortality rate is so low is due to the nurses per capita being higher than any other nation. If that were to be true, it would have to be in combination with other factors such as a higher ICU, more vigilant lockdown measures, etc. simply because other countries with similar and higher nurses per 1,000 have much higher mortality rates. Clearly, if that was the single biggest factor, Switzerland and Norway should have a much lower mortality rate.

My hypothesis, and the hope for South Africa, lies in the demographical composition of the nations and virus’s propensity to be more fatal the older the host.

Let’s look at the rate of infection per age group as it played out in China (remember they are a good two months before the rest of the world, so 11 Feb is good mature time to measure for them).

You will notice that the overall mortality at that stage was 2.3% where today it is 4.5%, mainly because of the weight and high mortality of Italy. Still, if we recalibrate these figure by assuming a uniform increase across all age segments, mortality for the 60+ age group becomes 11.8% as per below

Apply this to the relative population and you can work out a weighted average mortality rate as I did below

What does the above chart tel us?

To start with, the figures for Germany and Italy are not reflecting reality, but it does show that we should expect a lower mortality rate in Germany than in Italy. Similarly, because of the age demographic of the South Africa population, if and only if the population had a similar health profile, one would expect a mortality rate of only 1.6%.

What role will TB and AIDS play?

I think the final say in South Africa will be how much of a factor will TB and AIDS have in our population. Be all accounts we should expect a higher mortality rate because we have fewer nurses per 1,000 but we have 7.97 million South Africans living with AIDS. That means an immune system that is under severe strain and we know that fighting COVID-19 is all about the immune system.

Did I manage to answer my own question regarding Germany? I think not. I suspect PhD’s will be written on this question as it is puzzling. Did I, in the process of trying to test a hypothesis about the youthful demographic of the South African population learn something about our expected mortality rate? For sure. What I don’t know yet is what impact TB and AIDS will have…

So the question remains, will our youthfulness reduce our mortality rate or will we be able to emulate what the Germans are doing to keep the mortality rate as low as possible. I think neither, yet I hope I am wrong. Time will tell.

Stay safe. Stay at home.

Ed (30/3/20): Perhaps the chart below is the answer to the question. Source Financial Time via London Business School