Sanity check on unreported COVID-19 deaths

 The latest release of the NMG model includes an allowance for COVID-19 deaths not included in the official reported numbers. In this blog, I take a look at the South African Medical Research Council (MRC) estimates for natural deaths in 2020 by way of a sanity check on our modelling assumptions.

The MRC has published estimates for the natural deaths for persons aged one year and older for each of the first 33 weeks in 2020 (to the week commencing 12 August 2020). The estimated weekly deaths are compared against a forecast number of deaths that reflects the anticipated deaths for a year without a pandemic. The comparison is shown in the graph below:


When the MRC released their weekly report in July, they made an assertion that COVID-19 had caused 3 times as many deaths as the official reports show. The assertion resulted in a sharp reaction by the PANDA group (see https://www.pandata.org.za/excess-deaths-oddities/).

One of the observations made by PANDA was that lockdown could have caused a delay in the recording of deaths by Home Affairs which explains why the actual deaths line drops below the forecast deaths line for some weeks following the start of lockdown. The spike in actual deaths in June/July is then accentuated by the late recording of these old cases. This hypothesis would appear to be supported by the fall off in actual deaths following the July publication by MRC.

I have looked at the gap between the actual and forecast MRC deaths before and after 25 March to determine my own measure for 'excess deaths' caused by COVID-19:
  • Excess deaths recorded for the 12 weeks to 25 March 2020:  2680
  • Excess deaths recorded for the 21 weeks from 25 March 202:  24399
The excess deaths before 25 March 2020 would indicate that the MRC forecast numbers might be understating natural deaths for persons one year and older (as this is a period before any COVID-19 deaths were reported in South Africa). The excess deaths from 25 March 2020 might then be overstated to this extent.

The MRC forecast deaths include deaths due to seasonal flu that has been a feature of this analysis in prior years. There has been little evidence of seasonal flu in 2020, and to the extent that an adjustment is made for this, the excess deaths from 25 March 2020 will have been understated.

For the sake of this analysis, let us assumed that 24399 is a reasonable estimate for excess deaths caused by COVID-19. If I compare the 24399 with the forecasts provided by the NMG model, I can break this number down as follows:
  • Reported COVID-19 deaths for the 21 weeks from 25 March 2020:  12264
  • Unreported COVID-19 deaths for the 21 weeks from 25 March 2020:  5729
  • Excess natural deaths from other causes for the 21 weeks from 25 March 2020:  6406
This breakdown does not appear unreasonable given all of the uncertainties that we are dealing with.

So move along nothing further to look at here....

30 August 2020


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