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I just read a German article comparing influenza with COVID-19. There is a table with Mortality displacement (rates? cases?) and laboratory-confirmed cases of influenza.

I'm super confused by this table. I think I know what laborartory-confirmed death cases are:

  • A person dies and the symptoms indicated influenza
  • A sample (e.g. spit) is taken
  • The virus can be proven to be there
  • Other reasons for the death can be ruled out

I thought that Mortality displacement would be an estimation of the unknown cases: For many dead people there is not laboratory test.

But the two things that don't quite fit:

  1. The Mortality displacement is sometimes 0.
  2. The Mortality displacement is sometimes lower than the laboratory-confirmed cases, e.g. 2009/10.
  3. The Mortality displacement is sometimes vastly higher than the laboratory confirmed cases: 2008/09 the Mortality displacement was 18,800 and the laboratory-confirmed cases were 10.

Can somebody explain mortality displacement in a simple way?

Martin Thoma
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  • Are you asking about mortality displacement or about excess mortality? The linked article talks about excess mortality (Übersterblichkeit) only. – cbeleites unhappy with SX Apr 03 '20 at 20:21
  • I was asking about "Übersterblichkeit". I thought that was the correct translation as the wikipedia articles link to each other. Isn't that the case? – Martin Thoma Apr 03 '20 at 20:37
  • To solve the confusion in the body of the question, I recommend reading an RKI influenza season report, e.g. https://influenza.rki.de/Saisonberichte/2018.pdf. They explicitly state that numbers of deaths with lab-confirmed influenza are not a valid base for extrapolating "influenza deaths", for a variety of reasons. Moreover, they explain that influenza surveillance was reorganized around 2011. You may have noticed that the number of deaths with confirmed influenza infection jumps up by a factor of ≈10 around there. Tagesschau has a somewhat hidden hint that they composed the table. – cbeleites unhappy with SX Apr 03 '20 at 21:13

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It's the number of deaths an event has caused to be shifted in time. So，there's a very high rate of deaths right now from covid-19 in Italy amongst the older population. Those deaths are occurring now instead of in the future so those deaths are displaced from the future to now. As a result the number of deaths in the older population after the pandemic finishes will be less since they were displaced to a different time.

Graham Chiu
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  • I'm not entirely sure (since I'm not a native English speaker), but there may be an issue with the translation OP uses: while this explanation of mortality displacement makes sense to me, the linked article exclusively discusses excess mortality (so regardless of whether the excess deaths are followed by lower-than-expected death rates). – cbeleites unhappy with SX Apr 03 '20 at 20:19
  • I am only explaining mortality displacement which is what is being asked I don't read German. People are being odd if I'm being marked down for answering the question correctly when the OP has mistranslated the article! – Graham Chiu Apr 03 '20 at 21:00
  • Graham, I'm not marking you down. I was only puzzled since I perceived a discrepancy between the headline question, the body of the question and what is discussed in the linked article. Different topic: can you confirm my understanding that excess mortality in contrast is about having more deaths than seasonally expected - regardless of whether this is followed by a lower-than-expected death rate? Or, formulated in different manner: does mortality displacement imply the lower death rate being short to maybe medium term, i.e. just after the cause of the excess mortality is gone? – cbeleites unhappy with SX Apr 03 '20 at 21:08
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    Someone has marked down my answer. I didn't say it was you. – Graham Chiu Apr 03 '20 at 21:10