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"Ein Jahr Corona − wie Pathogene und Menschen sich gegenseitig beeinflussen" - Folge 10 des LNDW Podcasts. Fotomontage Portraits von mit Felix M. Key (Foto: Christian Denkhaus) und Dr. Eva Asselmann (Foto: Jens_ Gyarmat) auf einem Symbolbild (Foto: Kadmy –, das Menschen mit Maske und Handschuhen zeigt.

Felix M. Key (Foto: Christian Denkhaus) und Dr. Eva Asselmann (Foto: Jens_ Gyarmat), Symbolbild (Foto: Kadmy –

"One year of Corona – how pathogens and humans influence each other" (episode 10)

Since March 2020, the coronavirus responsible for the COVID-19 disease has been shaping public life in Germany. What impact do the pandemic and the measures to contain it have on mental health? And conversely, how do the measures affect the virus? Thomas Prinzler discusses these questions with his two guests in the tenth edition of the LNDW podcast. Dr Eva Asselmann is a research associate at the Institute of Psychology at Humboldt University Berlin. In the "Personality Psychology Working Group", her research includes the question of what influence drastic life events have on the development of personality. Felix Michael Key is researching the evolution of pathogens at the Max Planck Institute for Infection Biology. He and his team are primarily interested in uncovering the genetic mechanisms and phenotypic variations that underlie the emergence and adaptation of infectious microbes.

Thomas Prinzler: Which private or professional changes did you experience  within one year of Corona?

Dr Eva Asselmann: I research and teach at the university. Currently, teaching exclusively takes place in digital forms. Meetings with students take place online, either synchronously or asynchronously. Fortunately, I am adept at working from home a lot, so I am not much restricted in that regard. I have been able to adapt my daily research routine well to the new situation. I am also very happy with the digital formats we have found. It makes a lot of things easier. What works very well, for example, is the collaboration with people from abroad.

Felix Michael Key: A large part of my work takes place on the computer. Therefore, I have good preconditions for working in a home office. However, my wife and I have been working from home for months now, with our three small children. They are three and ten years old. This poses a challenge. We both have full-time jobs, which is exhausting. My wife is very involved in her work. As a researcher, I'm the one with the flexible schedule, so I can work at night and do home-schooling during the day and keep the youngest busy, so no one goes crazy at home.

Thomas Prinzler: Dr Asselmann, you are working on drastic life events. I assume that the Corona pandemic and its consequences are among them. What other events are these?

Dr Eva Asselmann: The corona pandemic is a collective life event that affects us all, to a greater or lesser degree. In personality psychology, drastic life events are understood as individual events that imply a significant upheaval. Examples are family and professional events, such as moving in with a partner, getting married, having children, entering the workforce, or retiring. All of these are typical times of upheaval that demand enormous adaptations from the individual – resulting in personality changes.

Thomas Prinzler:Many people react more thin-skinned. Are these possible signs that our personalities are changing due to the pandemic?

Dr Eva Asselmann: By personality changes we mean longer-term changes that extend over months, if not years. It would therefore be premature to say that these are personality changes. But it is a reaction to the mental health. There are already many studies on this. We have also been able to show during our research and studies that there is an increase in anxiety disorders, depressive symptoms, but also an increased stress load. We will have to see to what extent all of this will last beyond the pandemic.

Thomas Prinzler:What other insights could you obtain in your studies?

Dr Eva Asselmann: Our research looked at the role personality plays in dealing with the pandemic. We could show, for example, that mainly younger people are affected by the lockdown measures due to anxiety disorders and depressive symptoms.

Thomas Prinzler:That's surprising: younger people are particularly affected by loneliness?

Dr Eva Asselmann: There are many studies that show that even independently of COVID-19, people between the age of 20 and 30 suffer from feelings of loneliness more often than older people. We find this again in old adulthood, for example with people who are widowed. Younger people are often in a phase of transition, e.g., they have just moved out of home, but have not started their own family or have children yet. They are, therefore, much more socially flexible, more variable, but often have not yet found a connection and live as a single person. This can naturally lead to feeling lonely.

Thomas Prinzler:Mr Key, you are not a coronavirus specialist, but you do research on pathogens in general. Now it is said that the coronavirus was probably transmitted to humans by bats. That is evolution in action, correct?

Felix Michael Key: Yes, this is an example of the so-called zoonosis,  meaning, a disease that has jumped from animals to humans. My research group and I primarily work on reconstructing zoonoses that are thousands of years old. Zoonoses have been with humans for a very long time. Even in recent history, SARS-CoV2 is, at the bottom, nothing special – it happens regularly. What is extreme, however, is the extent to which we are experiencing it now.

Thomas Prinzler: We are currently observing that the coronavirus is emerging with new, more dangerous variants. What leads viruses and other pathogens to such mutations?

Felix Michael Key: From a very rational point of view, mutations are simply reading errors. When the blueprint of the virus is replicated, errors quickly occur. Imagine if you had to copy out a book, one or the other letter would get twisted. Mutations therefore occur randomly. Most mutations have no effect on the biology of the virus or other pathogens. It is possible that the mutation has a negative impact. But then it disappears again on its own. From time to time, however, it happens that a mutation results in an evolutionary advantage for the pathogen. In such cases, these mutations then get the upper hand.

Thomas Prinzler:With your working group, you are researching the history or evolution of pathogens and their adaptation to the environment, which includes us humans. How do you proceed with this?

Felix Michael Key: We work with the genome, the genetic blueprints, of pathogens, i.e., bacteria or viruses. Through comparisons, we look at the mutations that have contributed to their adaptation to humans. These are, for example, changes that lead to bacteria finding niches to settle in our microbiome. We are comparing two very different time levels: On the one hand, we are trying to reconstruct microbes that are thousands of years old, for example from old skeletal material of early farmers or hunter-gatherers. On the other hand, we analyse medical samples from clinics. There, we investigate, among other things, how bacteria can change within a few weeks. A typical example is that bacteria from the intestinal microbiome change in such a way that they can migrate to other parts of the body where they normally cannot survive and grow. In such cases, we go on to investigate which mutations are responsible for the bacteria finding a new niche.

Thomas Prinzler:When you are drilling old skeletons, how do you find evidence of pathogens there, possibly even those that still exist today?

Felix Michael Key: This is always linked to a bit of luck, -so it depends on coincidence. We may assume that thousands of years ago, many people died of infectious diseases. Nevertheless, these pathogens are rarely preserved in the skeletons. If people fell ill with a systemic disease, however, the pathogens were also present in the bloodstream. In this case, they are usually also present in the tooth because the tooth is supplied with blood. After death, they are locked in the tooth, similar to a safe. We usually only find snippets of the genome, but sometimes so many of them that we can reconstruct the genome based on the snippets. Then we can ask: What are the changes compared to today, how has the pathogen adapted?

Thomas Prinzler: Dr Asselmann, how should we deal with the risk posed by pathogens?

Dr Eva Asselmann: From a psychological point of view, it is important to be aware of the danger. For example, wearing a mask, keeping your distance, not meeting lots of people. It is not helpful to panic or be overly anxious. Right now, it is important to, for example, maintain certain routines in our daily lives. This stabilises us and helps us to do something for our well-being during this time, which is demanding and can drain our strength. Therefore, it is also important to plan enjoyable activities in our daily lives. Those who are at home alone can resolve to actively call people or arrange a video call.

Thomas Prinzler:Looking ahead beyond the pandemic: Should or must we change our way of life?

Dr Eva Asselmann: We have changed some behaviours in the pandemic. It will be exciting to see what stays with us. For example, we conduct many meetings digitally now and no longer travel around for every conversation. This could also help the environment in the future. In addition, we might appreciate one or two things more after the pandemic, such as simply being able to go out and meet other people.

Thomas Prinzler:The pandemic is a collective event. Will it change the social climate in the long run?

Dr Eva Asselmann: The question will be how much we will remember about the pandemic. Have we forgotten it in five or ten years, or will it burn itself into our collective memory? That is an exciting question, but I do not have an answer now.

Felix Michael Key: I assume that in five years' time we will still be thinking about Corona. The coronavirus will have established itself in our everyday lives – with a certain level of contamination, but without the pandemic effect that it currently has. For a significant part of the population, however, COVID-19 will probably remain a serious health threat. We will therefore have to continue to rely on vaccination. New variants will emerge that can overcome the given immunity. Corona will accompany us, just as the flu accompanies us.

Thomas Prinzler:Finally, a question for both of you: Will you pursue these and other questions in the future at the research location Berlin?

Dr Eva Asselmann: Berlin is a great place to do research because there are so many excellent universities and research institutions here. You can network and collaborate wonderfully in Berlin.

Thomas Prinzler:Mr Key, you studied at MIT but decided to go to Berlin. Why?

Felix Michael Key: MIT in Boston is, of course, an insanely good research location with incredible expertise that Berlin probably cannot quite hold a candle to. Nevertheless, Berlin scores with an incredible number of bright minds. It is an exciting environment. I am at the Max Planck Institute, a place that is all about being able to do research efficiently. It is a great environment. Since I am in the process of setting up my research group, I can also say that Berlin is a magnet for young researchers from all over the world – including those from Boston. That is why I don't miss anything here at the moment.


Felix M. Key and his research group: Key Lab | Max Planck Institute for Infection Biology (

Dr. Eva Asselmann: Department of Psychology (

Due to the pandemic, the conversation was recorded remotely via app. The transcript of the conversation differs slightly from the original for better readability. The complete conversation can be listened to in the ARD Audiothek.