'It’s about the excitement'

November 21, 2019

Matthieu Domenech de Cellès started his position as MPIIB research group leader in October. He heads the new group “Infectious Disease Epidemiology”. With his epidemiological research, the trained mathematician will provide a new perspective on infection biology for the MPIIB. In the interview, Domenech de Cellès talks about his first weeks at the institute, future research plans on mathematical modelling and the importance of vaccine coverage for the fight against infectious diseases.

Mr. Domenech de Cellès, you started in October–what are your plans for the first months?

I had very easy and smooth first weeks at the institute. I could get started right away–fortunately, a computer and some IT infrastructure are sufficient for my research. I didn’t have to set up a whole wet lab like Igor [Iatsenko] for example. Now, I am working on writing my research projects before I start advertising for positions.

At the same time, I am trying to meet people to establish collaborations for my future research projects and to get familiar with the environment here at the Charité campus. I am also in contact with some people at the Robert Koch Institute, since I am dependent on epidemiological data for my research. I need the data to test hypotheses and build mathematical models. So, it will be quite important for me to collaborate with people in charge of disease surveillance in Germany.

What motivated you to join the MPIIB?

I have to confess, I didn't know about this particular Max Planck Institute when I saw the job advertisement last year. I first thought the research here was focused on basic biology, but the call was for a very broad range of disciplines linked to infection biology. And even though I do mathematics, I am very interested in understanding the biology of infections. I wasn’t sure if the committee would accept someone with a mathematical background like me, but in the end it worked. Since I joined the MPIIB, I discovered that many other researchers at the institute actually use mathematical approaches. This is quite promising for me as there are many opportunities for future collaborations.

How do you feel about your new role as research group leader?

Thinking about my new role was a bit intimidating at first, but people have been very friendly and helpful. I already supervised some students when I was a postdoc, but this is something different. In order to develop my leadership skills I am following seminars and reading books on this topic. It's really exciting because I am at a point of my career, where I can develop my ideas. And I will need a good team for this endeavour!

Was there anything surprising about the life in Berlin?

So far, I am enjoying Berlin very much, but I am not too surprised. It's a European city in a European country after all and actually not very different from Paris. Of course, there are some small differences: People are very friendly and the city is more relaxed than Paris for example. I also found that you can get by quite well speaking English. This is helpful, but at the same time a bit unfortunate–I rarely get a chance to improve my German language skills. I have a great time in Berlin, I like the city very much and I am excited to be in this vibrant environment.  

What were the steps of your career so far?

I have a background in quantitative sciences: I graduated from an engineering school in France, where I was trained in mathematics and physics. Then, I did my PhD at the Institut Pasteur in Paris, where I started working in infectious disease epidemiology. This was about developing mathematical models of transmission to understand the spread of infectious diseases. The research was focused on antibiotic resistance and vaccines – especially vaccine effectiveness and vaccine efficacy.

After my PhD I went abroad to do a postdoc at the University of Michigan. For two years, I was working on the epidemiology of whooping cough, pertussis. This respiratory infection is vaccine preventable, but the number of cases has been increasing in some countries, including the US. During my postdoc I developed and designed mathematical models to understand this resurgence of pertussis.

For my second postdoc I returned to the Pasteur Institute. At Pasteur, I started working on pneumococcus. The bacterium causes many different diseases, for example pneumonia or meningitis in children. I was especially interested in the seasonality of pneumococcus infections and tried to understand how and why the infections where seasonally distributed throughout the year. For example, in Germany and France we observe a peak of disease incidence during winter, and it is not well understood why we observe this strong seasonality. In my research, I again tried to develop models to test hypotheses about the origin of the seasonality of pneumococcal infections.

It’s not only about a weakened immune system because we are cold in winter?

This is only one of the hypotheses focusing on the human host. Cold weather could also affect the survival of the pathogen. There are studies showing that, for example, some viruses survive longer in a colder climate. Then you have several hypotheses linked to the behaviour of humans. For example, children make more contact, when they are at school, which may raise the transmission rates of diseases. All kinds of different hypotheses exist and need to be incorporated into a single model, if you want to understand what is going on. And that is basically what I am trying to do in my research.

All in all, the foundation for my research interest was laid during my two postdoc periods: I am interested in vaccine epidemiology, understanding the vaccine effectiveness in human populations and I am trying to understand the seasonality of infectious diseases.

There is a general trend in biology towards modelling...

Right, it can take different forms. Everyone talks about big data and using artificial intelligence for research at the moment. This is more on the statistical side, using statistical methods to extract information from very large and complex data sets. Maybe I will do that at some point, but for the moment, I am still trying to understand how the system works using mathematical models – setting up equations and analysing how variables influence each other. There are, however, more and more people working with very complex mathematical and statistical methods to do biology. It will be very interesting to follow this development in the years to come.

What are your thoughts on the rise of anti-vaccination groups? Does that affect your models?

It does affect our models! It’s a big problem and there is a lot of research trying to understand why people decide not to vaccinate. Some people don't seem to realize the dangerousness and the severity of many diseases that are vaccine preventable, like pertussis or measles. Actually, I would like to follow this line of research to understand the social determinants of vaccine hesitancy. At first, I thought it was only in the US but now it's spreading in Europe. You can find anti-vaccination groups in France and I heard you have this problem in Berlin as well. In France, there was recently a big resurgence of measles. Researchers discovered that the vaccine coverage rates were dropping. Consequently, there is now a law that makes the vaccination compulsory for 11 paediatric vaccines. People have to understand that a high vaccination coverage is essential: If you release the pressure, the disease comes back!

What do you personally enjoy about doing science?

I think it’s all about the excitement! It comes at two stages: The first one is when you have a good initial idea about doing a research project. This is already exciting. The second step takes a lot more time. You test your ideas and many times, it won’t work, but then there is this moment where something does work: You know you have found something very important. This is the second step of excitement, which is very, very cool. So for me, research is just about the excitement of trying to discover new things.

The interview was conducted by Christian Denkhaus.

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