• Frederike Schmitz

And then corona started and Didi moved to the lung


Photo by Diana Parkhouse on Unsplash

In April 2020 the corona crisis hit us. All of us, all over the world. A pandemic.

During my studies, I’ve learned about the history of pandemics. And yes, I also had a lecturer who would tell us that it’s inevitable that we will experience a pandemic at one point. It was not a matter of if but when.

And I believed them. Yet, I – like probably so many of you- would have never thought that this happened in my lifetime.

But then it did. Well it does.

Still, it’s not yet over.


Early in the pandemic it was the epidemiologists who would be in the spotlight. Explaining to us how viruses spread through populations. Measuring this and through modeling, attempting to predict the future.

Then came the virologists. They explained to us what this virus is, what measures we could take to prevent infection.

And then eventually it was and still is time for the immunologists. They can tell us how our immune cells fight this virus.

And how vaccines work.

These we urgently need in order to return to ‘normal’ life.


Right when the covid-19 crisis started I experienced a period of confusion and fear.

What was about to happen?

This soon got replaced by a feeling of urgently wanting to do something. Something useful.

After all, I was a trained immunologist. There had to be something I could do.

But I’m not working in a lab anymore. I’m not an active researcher anymore.


It soon dawned on me that I could maybe help by explaining how the immune system works.

Back then I realized that I had already written a story about immune cells fighting a virus.

Well, this story took place in the intestine.

So, I read as much as I could about SARS-CoV-2, the virus which causes covid-19.

And I concluded that the immune response as far as I could judge was very much according to textbook immunology.

Roughly what one would expect from a viral infection in the airways and lung.

So, I rewrote the part of the intestine story into a stand-alone story taking place in the lung.

I used SARS-CoV-2 as a model virus for the story, but I wanted to keep it general.

Since it is a new virus for us all, we are pretty much in the same situation as a newborn baby is when she meets a virus for the first time. Well, technically speaking.

There are of course numerous differences between the immune system of us, older people, in comparison to a newborn.

But the principle stays the same: to meet something new for the very first time.


In my revised story I never called this virus by its name. You can easily replace this virus with other respiratory viruses. As I said- this is textbook immunology.

Actually, it’s also not a whole lot different from a virus in the gut. After all the lung, as well as the gut are both- what we call- mucosal organs. That is, they are full of mucus.

Literally and figuratively.

They work in a similar fashion. They both form a unique environment, have unique immune features because they are places where we have direct contact to the outside world.

In immunology there is even such a thing as the study of mucosal immunology.

This is exactly what I did my PhD in.

Yummy mucus stuff :)


Overall, the whole corona situation also solved a problem for me.

I realized that I could and should split up the massive story I had written into smaller stand-alone stories. And that this worked much better.

It’s easier to digest than the mammoth story I’ve written before.


So just like that I had the potential material for 4 stories:

Story 1: What happens when you meet a virus for the first time? (this time in the lung)

Story 2: What happens after birth when bacteria settle down in your gut?

Story 3: How do cells communicate and coordinate? (the principle of the lymphatic system)

Story 4: How to kick out a fungus?


But the one I’m currently finalizing is the one where Didi meets a virus for the first time.

It is probably what interests kids the most right now.


I’m hoping that this will get them, and you hooked on immunology and make you want to know more about the amazing life of our immune cells deep down inside our body.



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