When the new coronavirus (SARS-CoV-2) spread across the world at the beginning of the year and the number of infected people grew exponentially, the COVID-19 death rates initially rose sharply in many Western countries such as Italy, Great Britain and the USA. They reached their peak to date between the end of April and mid-May (see graphic).
Germany’s increase was comparatively low. The main reason for the higher death rates was that many more elderly people fell ill, and the infection was often more severe. In addition, initially only infected people with symptoms were tested, so that the statistics did not include many younger people who showed little or no symptoms.
New infections high, death rates down
Because death rates are falling again, especially in Europe and the USA, despite rising new infections, and according to data from the online platform “Our World in Data“have leveled off at a low single-digit range, it is worth taking a look at the possible causes. These are diverse, but for many experts one main reason stands out.” The currently observed decline in the proportion of deceased among the reported cases [in Deutschland, Anm. d. Redaktion] can primarily be explained by the relatively high proportion of younger people among the newly diagnosed cases, of which relatively few become seriously ill and die, ”writes the Robert Koch Institute (RKI) in its COVID-19 management report from September 8th.
Secondly, the increased number of tests and, to a lesser extent, the increased number of asymptomatic people such as contacts with infected people have been tested for some months now, the RKI continues. Since the beginning of September, the weekly backlog in the test laboratories, which was caused by delivery problems with test reagents, has also decreased. If the samples are processed faster, the number of infected people and deaths can be determined more up-to-date and more precisely, and the death rate can be calculated from this.
For the case fatality rate (CFR), the number of confirmed Covid-19 deaths was divided by the number of confirmed COVID-19 cases. The result is an approximation, as, for example, asymptomatic infected people are not recorded in the case numbers and, especially in the first weeks of the pandemic, atypical Covid 19 deaths – such as strokes, heart attacks and pulmonary embolisms caused by the disturbed blood clotting – were not recognized as such. The death rate can vary depending on the location and circumstances such as increased testing capacity. This death rate should not be confused with the actual infection fatality rate (IFR), which cannot currently be calculated because one would have to know all deaths and all infections.
What is the change?
Jennifer Dowd also counts more young people infected and increased test capacities to be one of the main reasons for the lower death rate in Great Britain. Added to this is “the improved intensive care for severe cases, there has definitely been a learning curve,” says the demographer and epidemiologist from the University of Oxford. “There is evidence that the death rate in intensive care units has fallen.” For example, the University of Bristol and the Royal United Hospitals Bath NHS Trust reported in one in mid-July Meta-analysis in the specialist journal “Anesthaesia”that the intensive care unit corona death rates in Europe, North America and Asia fell by a third from 59.9 percent to 41.6 percent in the examined period from the end of March to the end of May.
Uwe Janssens, President of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI), emphasizes which treatments have actually contributed to this. “The advantage of corticosteroids in ventilated patients is relatively clear,” says chief physician of the Clinic for Internal Medicine and Internal Medicine at St. Antonius Hospital in Eschweiler. Preliminary results A UK study, which has not yet appeared in a peer-reviewed journal, showed a 36 percent relative risk reduction in mortality when patients received the anti-inflammatory and immune-suppressing agent. “That’s a lot,” says Janssens. In patients who received oxygen through a mask, treatment with the corticosteroid dexamethasone reduced the death rate by a relative 18 percent.
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Blood thinners “are certainly used in all patients as thrombosis prophylaxis because it has been recognized that SARS-CoV-2 increases the tendency to clot”. Doctors were also eagerly awaiting data on the monoclonal antibody tocilizumab, which is said to reduce the risk of a cytokine storm, i.e. a life-threatening excessive immune reaction. “Overall, we have also learned to look much more closely at the patients in order to quickly recognize deterioration even when they seem to be doing well,” explains Janssens.
Imaging and altered behavior
“We use imaging techniques such as computed tomography, in particular, to see whether the lungs have already been severely affected.” Last but not least, the changed behavior of the population plays a positive role. The elderly and chronically ill immunocompromised are protected, “that’s why we see them much less”. Although many complain about the security measures, most adhered to them, if not as consistently as they used to.
Death rates will only be able to be determined precisely after some time, says US demographer Andrew Noymer of the University of California at Irvine. In the USA, the processing and root cause analysis for the mortality statistics from 2018 took around 13 months. The data appeared at the end of January this year.
It remains to be seen what influence the Covid 19 infections, which are rising again in many European countries, will have on the death rate. “If older people become infected again, a resurgence in hospitalizations and deaths must be expected,” writes the RKI.