Why do we concern ourselves with COVID-19

The COVID-19 pandemic is the dominant topic for our customers. Currently almost all of them are in an „emergency“ mode: How do we organise our company, to be able to handle this crisis in the best way? One of the key pieces of information for this question is, how this pandemic will spread and evolve both in Germany and the world. In order to help you answer this question, we are providing you our System-Dynamics model, which is being updated on a daily basis.


Prof. Dr. rer. nat. Bo Hu is a professor of economics, with a focus on business information technology. and dean of the institute of management at the Universität der Bundeswehr in Munich, Germany. Since the outbreak of the epidemic in China, Prof. Hu has analysed the data of the city of Wuhan, the province of Hubei and all of China in great detail. Based upon this analysis, he has developed a System-Dynamics model, which shows the infection- and spread dynamics of COVID-19 in such a way, that the protective measures taken can be integrated and simulated.

The model for Germany

A key to limiting the CORONA pandemic, is a behaviour change on behalf of all of us:

So, please reduce direct social contacts with others and in case they do take place, keep your distance, ensure a high frequency of washing your hands etc. All of these actions should reduce the rate of infection and thereby slow down the spread of the virus. However, more and more people are now asking themselves, how these changes in behaviour actually effect the spread of the virus, as well as the  prescribed lock-downs. The following systems model attempts to provide answers to these questions, which Prof. Dr. Hu, of the Universität der Bundeswehr has developed in cooperation with the HORUS ADVISORY GROUP. The model shows the cumulative number of infected people in Germany, since the 01.01.2020 (brown curve), in addition to those people, who are infected, but have not been diagnosed yet in Germany (blue curve). The deciding parameter for the evolution of the pandemic is the rate of infection. The key determining factor for the infection rate is the so called frequency of contact.

Frequency of contact is defined as the number of (norm-) contacts of one person per day, which will lead to an infection with a probability of 1%, in case one of the people is infected with the virus. An example of this could be meeting somebody at a distance of less than 1m. Closer contacts, for example shaking hands increase this probability from 1% to 2% or even more. According to Prof. Dr. med. Christian Drosten, the probability of infection of a doctor lies at 5% during a 15 minute consultation. This is the equivalent of 5 (norm-) contacts for every patient consultation.

Based upon the report bout infections in Germany, we can derive, that the reate of infection until the 16th of March 2020 was at a rate of 18%. In other words, on average, every German had 18 contacts per day with a probability of infection of 1%. During the carnival season, this rate of infection even increased to 26 per day, due to the closer proximity of the people and the higher frequency of contact. Without a change in behaviour, the pandemic would spread exponentially beyond the 31st of May of 2020.

The number of confirmed cases on the 31.05.2020 would be at a level of close to 2,5 million! In addition to this, we would have over one million people, whose infection would not have been diagnosed yet. Our health system would have to treat in excess of 500,0000 severe or intensive cases and would be overwhelmed – with catastrophic consequences. Over 100,000 people would die in Germany alone.

In China the government was able to, with very drastic measures, reduce the frequency of contact to less than 4. In Germany, reduction of the rate of contact to a value of under 12 would be desirable. This would enable us to return to normality soon.

Our conclusion: Please keep your distance, reduction of contacts is a deciding factor. If  all of us manage to change our behaviour just a little bit, then this would be the deciding factor and would save numerous lives.

We will from now on provide you daily updates of the spread of the pandemic, where you are able to see the effectiveness of the implemented measures. Also, we are working on similar models for different markets at the same time.

Aktuelle Informationen zur COVID-19 Entwicklung

Prof. Dr. Bo Hu

Prof. Dr. Bo Hu

20th of March 2020 23:17

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Unfortunately, after the end of carnival, the ski season and the school closures, the rate of infection has not decreased as much, as we had hoped. The calculated rate of infection is currently at 23%, 5% points higher than the historical value of 18%. Should we not be able to reduce this rate of infection, we would have about 27 million people infected with COVID-19 by the 31st of May 2020.

23rd of March 2020 19:25

The tightened measures to reduce the rate of infection have not yet shown a deciding effect. The current value lies at 22%. Although this decrease of one percentage point, compared to last week, will reduce the number of people infected by the Corona virus by approximately 9 million. However we would still be far away from a patient number, which could be handled by the health care system. Now, we need to watch the development over the following days.

24th of March 2020 20:08

The lock down finally seems to show an effect. The current rate of infection lies between 12-14%. At this point in time, we would like to mention that we calculate with a delay of 6,5 days between infection and diagnosis. Should the current value remain stable, we can expect over 180,000 infected, both confirmed and unconfirmed by the 31st of May 2020. This level would be sufficiently low, so that the German health care system would still be able to handle it. However at this level, the economy cannot go back to its normal operating mode. For this we would need a lower level, for example to be able to conduct a Korean approach in handling the outbreak.

25th of March 2020 18:14

The rate of infection seems to stabilise. However it is too early for a prognosis at this point in time. Hopefully the next few days will show the positive effects of the lockdown.

26th of March 2020 20:02

According to our calculations, the current rate of infection is now at 14, having risen slightly. This approach of using the rate of newly infected to the total number of infections is a good indicator. However this model has an uncertainty, the number of cases, where the exposure took place outside of Germany. This uncertainty has the potential to distort the result. On the positive side, the number of Corona tests in Germany has increased considerably. Whereas, according to the Kassenärztliche Vereinigung, 35,000 tests were performed in Germany, in the week of the 6th of March, the number has increased to 410,000 tests as of to date. According to the head of the Kassenärztliche Vereinigung, Andreas Gassen, Germany now is at the top in tests per capita. He expects an increase in the testing capacity to the level of 360,000 tests per week.

27th of March 2020 17:45

The infection rate stabilises itself with a positive tendency. The relatively high number of new infections is also partly caused by the large number of exposures, which took place abroad. To dat, the RKI has reported 6548 cases imported from Austria, and 1384 cases from Italy, followed by Spain with 230 cases. Accordingly the foreign exposures are playing a considerable role in the total number of cases. As the effects of the tightened lockdown should be seen beginning with next week. Therefore we are looking with great interest to next week monday.

30th of March 2020 20:57

It seems to confirm itself that the peak of new infections has been reached on the 27th of March 2020 with 6465 newly infected. Today’s value at 21:00 is at 3811 infected. Also does the RKI no longer report outside exposure infections. Therefore the current cases are only domestically infected cases. Unfortunately the lockdown does not show the expected results. It is already becoming clear that COVID-19 will hit Germany harder than China. While in the province of Guangdong, with a population of 100 million about 1500 COVID cases were reported, just the city of Munich alone, with its population of 1,3 million already has reported 2500 cases. Also the current rate remains stable at 14% and has not decreased as we had hoped.

2nd of April 2020 18:27


the rate of infections / contacts in Germany has stabilised itself at a rate of 14. The good news is, that with this rate of infection, the capacities of the German health system will most likely not be overwhelmed. Therefore, we have the substantiated hope that Germany will be spared a situation, as in Bergamo, Madrid or in Alsace. A great cause of concern however is still that we see thousands of newly infected people. The approach, which was previously presented by us to reduce the number of new infections to several hundred (phase 1) and then to return to a normal mode of operation with higher testing rates, the currently discussed mobile phone app and a mask wearing requirement (phase 2), has become far less likely under the current conditions. If the rate of infection remains also in the following days at this level, a transfer towards phase 2 (see below) around the 20th of April becomes very unlikely. We currently expect rather for this change in policy to take place in the month of May. Also will the restrictions only be lifted in a step by step scenario – with the according negative effects on consumption in the months of May and June. A normalisation is therefore not expected before July 2020.


The spread of the epidemic in the United States is a deciding factor for the development of the global economy. Therefore we follow closely the development of the outbreak and have developed a model for the US. Based upon this model, we would describe the current situation there as being of great concern. Our model shows why the American President has made such a drastic correction in his management of the Corona crisis. There is no longer any mentioning of lifting the restrictions prior to the Easter holidays. Whereas a few days ago about 100,000 deaths were expected and viewed as an optimistic result, we believe that this number is unfortunately rather too optimistic. In the press briefing of the US President on the 31st of March 2020, he already mentioned 240,000 expected deaths. According to our model the pandemic will develop as follows in the USA:

The current rate of infection lies 10% points higher in the United States than in Germany. Under these circumstances, a total of 28 million infected victims can be expected by the 30th of April. Until the 31st of May, this number could actually increase to 198 million people, which would equal the infection of approximately 60% of the population. Taking the average mortality rate published by the WHO of 3,4% into consideration, then we face the risk of seeing 950,000 deaths in the United States by the 30th of April. In order to limit the number of COVID-19 deaths to a number of below 240,000, the rate of infection would have to be permanently reduced to the current German level of 14% until the end of May. In Germany this was achieved by a strict lockdown. Therefore it is unlikely that the American economy will be „Open for Business“ again by the middle of May, unless a much higher mortality rate is accepted, which of cours would also have strong negative effects on the economy.

Japan and other countries

Our model for Japan shows that the Japanese approach regarding the measurement of the COVID-19 development varies considerably from that of Germany and other countries. In order to make the official Japanese numbers of newly infected comparable to the Geman numbers, they should be multiplied by a factor of 3.5.

7th of April 2020 09:00

Tendencies of the lock-down

The contact frequency has risen to 15% during the last days. Also in China and South Korea have the numbers of infected slowly increased again. Japan will actually implement a state of emergency until the 06th of May 2020. The lock-down in Germany has to be improved. In this context, would the mandatory wearing of face masks be quite useful. Even, if the face masks would only provide a 10% reduction of infection, this would mean a reduction in the rate of infection from 15% to 14%.

7th of April 2020 17:00

Due to the high number of intensive care capacities per capita in Germany, we are gaining confidence in the trend, that the health cares system is able to handle the number of infected people. In this context, we do not expect the lock-down to be lifted before May. A realistic future scenario for the period following the month of May will be a level of new infections of 500 per day. In this scenario we would have approximately 180,000 infected by autumn of this year.

8th of April 2020 19:06

At the moment, we believe that the rate of daily new infections will be reduced to 2000 by the 1st of May. Therefore we expect a lifting of certain measures of the lock-down in Germany. After this lifting, the contact frequency will increase again from 12 to 16. However, due to the expected introduction of the app, we expect at the same time that the period between infection and diagnosis will decrease from 6,5 days to 5,5 days on average.

14th of April 2020 18:08

Based upon our model, we deem a reopening of the schools in Germany on the 20th of April 2020 as unlikely, especially for Bavaria. We believe that it will be more likely that the schools will be reopened around the 1st of May 2020, in conjunction with the implementation of the tracking app.  A key factor will be the acceptance of the app. In order for the app to reduce the time period between infection and diagnosis to 5.5 days, it needs to have an acceptance rate of 60%. Current experiences from the Chinese province of Henan are not very optimistic. Currently only 14 Mio. use the mandatory app, out of a total population of 96 Mio., eventhough this app is mandatory for being able to move freely. Busses or supermarkets may only be entered by people registering their app at these locations. Therefore the majority of the population prefers to remain at home, which of course is also beneficial from an infection point of view.

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