Coronavirus: The problem with the number of cases
Florian Tiefenböck studied human medicine at the LMU Munich. In March 2014, he joined as a student and has supported the editorial team with medical articles ever since. After receiving his medical license and practical work in internal medicine at the University Hospital Augsburg, he has been a permanent member of the team since December 2019 and, among other things, ensures the medical quality of the tools.
More posts by Florian Tiefenböck All content is checked by medical journalists.Sars-CoV-2 continues to spread. But the numbers are seldom uniform. At the weekend there was confusion when the Robert Koch Institute published the new case numbers for the coronavirus. The background, where the numbers come from and what they mean, can be found in this post.
The Robert Koch Institute (RKI) reports daily on the current situation in the corona crisis. In addition to a lot of information about the novel coronavirus and Covid-19, the RKI also presents official registration data.
Confusion about corona case numbers
At the weekend, however, the RKI caused confusion after it had updated the statistics on new infections with the Sars-Cov-2 pathogen.
On Sunday, the RKI reported 18,610 infected people. According to this number, 1,948 people were newly infected with the corona virus compared to the previous day. The day before, the number of new infections was significantly higher - namely at 2,705.
Some media then reported that the spread of the novel coronavirus had slowed. According to the RKI figures, there would have been 757 fewer new infections. However, there were significant deviations from other reports - such as those from Johns Hopkins University.
The Johns Hopkins University provided other figures
Apart from the RKI, the Johns Hopkins University (JHU) also provides current case numbers. The university operates the Johns Hopkins Coronavirus Resource Center, a website that interactively displays corona numbers for various countries around the world.
On the night of Sunday, the card showed more than 20,000 corona cases in Germany - and thus significantly more than the RKI. But even after the daily update on Sunday, the RKI numbers remained below the 20,000 mark.
According to the information from Johns Hopkins University, the novel coronavirus is clearly on the rise. Deviations could also be seen in the deaths from Covid-19. Here the JHU showed a lot more than the RKI.
Opinion of the RKI
The Robert Koch Institute thereupon commented on its website: “At the current weekend, not all offices have transmitted data, so that the increase in the number of cases reported here does not correspond to the actual increase in the number of cases. The data will be forwarded on Monday and will also be available in these statistics from Tuesday. "
At this point in time, there could be no question of a slowed-down spread. Various media withdrew their press reports about the supposed all-clear regarding the spread of the coronavirus.
Why are there different numbers of cases?
If you want to know how many people in Germany, but also worldwide, have been infected with the new type of coronavirus, there are primarily these three reliable sources:
- The Robert Koch Institute,
- The World Health Organization (WHO)
- The Johns Hopkins University (JHU) website
The three organizations collect data about the coronavirus - but in different ways. This gives them different numbers. In addition, the numbers are updated at different rates.
Where do the numbers come from?
To understand why there are different numbers of cases, it helps to take a look at how the organizations work and where the RKI, WHO and JHU get their numbers from.
Robert Koch Institute
The Robert Koch Institute is an independent German higher federal authority and is responsible, among other things, for infectious diseases such as Covid-19. For example, it records officially reported infections and deaths and publishes them.
The reporting channel of the RKI
If a person is infected with Sars-CoV-2, the case is reported to the responsible health department. There are around 400 such health authorities in Germany. They transmit - no later than the next working day - the positive cases of the region for which they are responsible to the appropriate state office.
First health office, then state office
The health department in Munich, for example, forwards the detected infections in Munich and the surrounding area to the Bavarian State Office for Health and Food Safety. Coronavirus numbers are also received there from all other health authorities in Bavarian cities and municipalities.
The state offices in turn transmit the number of cases to the Robert Koch Institute. The RKI automatically checks these figures again and publishes or updates the overview on its website. This will need time. The numbers are updated once a day.
Long journeys cause delays
Even if the authorities now largely transmit their coronavirus case numbers electronically, there are delays along the long reporting path. In addition, the RKI updates its data exactly once a day - at 10:00 a.m. with a data status from midnight before.
The WHO numbers
The World Health Organization (WHO) relies on the officially reported figures published by the RKI. The numbers are therefore often even further behind.
The Johns Hopkins University coronavirus numbers
Other sources bring the infection numbers up to date much more frequently than the RKI. This is because they do not obtain their data via the long, official reporting channel. The best-known alternative to the RKI numbers is offered by Johns Hopkins University (JHU).
The program of this private university in Baltimore, USA was built by a professor of systems engineering - Lauren Gardner - and a student named Ensheng Dong to illustrate the coronavirus cases worldwide.
No waiting
In contrast to the RKI, the JHU employees do not have to wait for the official reports. Instead, they draw their data from freely accessible sources. These include, for example, the websites of the health authorities and reports that are distributed by official authorities on social media channels.
Reliable numbers
The JHU only uses official and credible sources for its research. Therefore, your numbers on the novel coronavirus are just as suitable for obtaining reliable infection numbers and tracking the spread of the coronavirus.
Danger: high number of unreported cases
But no matter which source you use, the published figures can be deceiving. On the one hand, it remains unclear how many infected and sick people are healthy again or at least no longer contagious.
On the other hand, by far not all infected people are recognized. One of the reasons for this is that not every Sars-CoV-2 infected person develops and tests symptoms.
For Germany, experts estimate that five to ten times as many people are infected than you actually know from corona tests. This is what makes assessing actual spread so difficult.
You can find out more about the number of unreported cases of coronavirus infections and how to deal with them in our article "Corona: How high is the number of unreported cases?"
