“As a scientist, I don’t give political advice.”

Interviewed by Lionel Pousaz, Independent Science Journalist & Writer
Experts Speak: Emma Hodcroft

18th Feb 2021

Unknown to the public a year ago, Emma Hodcroft has become a public figure among scientists discussing COVID-19. A molecular epidemiologist at the University of Bern, she appeared in many news outlets around the world. On social networks, she has become increasingly popular with her takes on the many aspects of the pandemic, from the virus mutation to supply chain failures. She is also a co-developer of the Nextstrain project, a public data platform on pathogens genomes and evolution. She tells her story and explains why science communication matters now more than ever.

Cover Illustration Credits: Alex Cagan | Photo Credits: Oliver Hochstrasse

During the first months of COVID-19, you emerged as one of the most popular scientists on Twitter. Can you tell us how it happened?

Before the pandemic, I did not have much of an audience. Like many scientists, I would just share preprints about my research work. It was nothing like what I am doing now. I remember the end of January, I was back in Texas and I showed my mother a Twitter post about my work. I was proud of my 800 followers. This memory sets a point in time. Now, I have about 52,000 followers. It first took off when I sent one of my first long Twitter threads about the pandemic on my phone, from my bed. At the time, governments advised storing food and essential medication at home. Many people were taking this as a sign of panic, that we might run out of food. I explained that it would just help if people had enough food at home and did not need to leave the house every day to shop for groceries. It is even more true if supply chains are disrupted as it happened in China. It did not end up being that bad in Europe, but at the time we did not know.

We all remember people hoarding food and empty shelves in supermarkets. It was a confusing period.

The logic behind it was not obvious: why should we run out of food because of an infectious disease? It infects humans, it is not going to kill the crops, and it is not going to make the canned food explode. People were not clear about the government’s expectations. Many worried that the authorities might be hiding something. The real problem, I explained, is that our supply chains are run by people. If we have to limit how much we move around, or if a lot of us are sick, then supply chains might suffer. It was very comforting for people to understand the logic of the government. With the knowledge we had at that time, it made a lot of sense.

Your most successful posts are intended for the general public. How do you decide the topic, the specific angle?

I try to use my expertise to answer questions that a lot of people have, but that aren’t being answered through other media or announcements. It is important to share more scientific information – such as discoveries – but a lot of my threads are centered around basic questions. Another example is a thread I wrote about excess mortality. It is a basic concept for scientists. But in April, it kind of cropped up out of nowhere in the public. I wrote a simple thread about what it means, and why it is an interesting number to look at. It became quite popular. Of course, it is not a topic you have to explain to scientists. They know what it is about. But it means a lot to the public if you can communicate it clearly. It helps people to make sense of something they have heard in other contexts, but that they might not fully understand.

You care a lot about language and structure to keep your message as accessible as possible. How much commitment does it require?

A lot. If I have a good idea for a Twitter thread, and if I am feeling strongly about it, I can spend six hours writing, researching, condensing, and perfecting it. I try to make it the most understandable I can. Unfortunately, I don’t always have that luxury of time. But I have certainly done that.

Do you write differently when you address your scientific peers?

If I use Twitter to discuss a topic a little more niche, my main concern is that I am still exposed to the general public. I try to remain aware that many non-scientists will be reading it. I cannot always write every thread so that it is fully comprehensible to a layperson. It would be far too long. But I try to make sure that nothing can be misinterpreted. I am not always successful, but I always keep this concern in my mind. Even when I write something more technical, I always try not to leave room for misunderstanding. I don’t want to let people think that the situation is worse or better than I’m trying to convey.

I imagine it is not always easy to bring these extra details and cautions with only 240 characters.

No, it isn’t. In my more niche threads, when I have enough time and character space, I try to put in little things to help non-experts understand. For example, I did that in one of my recent threads about COVID-19 spike protein. I said something like “the most sticky bit of the virus” or “the bit of the virus the body recognizes”. I don’t need to tell that to scientists. Likewise, it is not going to be enough on its own if you know nothing about viruses. But it might be an extra little handle to understand better why we should care about mutations in the spike.

You were also featured quite often in general media, such as TVs or newspapers. How did it start?

My first interview was with CBC (Canadian Broadcasting Corporation). They might have gotten referred to me by other scientists. Then, many other news outlets have followed, like Bloomberg, the BBC, and the Wall Street Journal. It took a little longer for the Swiss media, maybe because I was not particularly well known as a scientist. Also, I don’t speak German well enough to talk about science. I have made my first couple of connections in Switzerland through the Nextstrain Project, which I have co-developed. There was a growing interest in it. People wanted to know what we could learn about virus mutations.

How would you describe your personal experience with the media?

So far, most of it has been pretty good. I am a little picky about whom I speak to. I try to make sure requests come from legitimate news outlets. I choose media that seem to have a real interest in reporting on what they hear, rather than trying to fit the narrative around their ideas. I am also pretty strict about being able to check my quotes before the article goes out. Of course, even if your quotes look good, they might appear in a context that is a little different from what you had pictured. Sometimes, the surrounding paragraph is not something I would have supported myself. But you cannot entirely protect yourself against this.

What do you think about popular but less reliable media? Do you always decline their requests?

I have an interesting story about this. A little while ago, I received an inquiry from a European newspaper that is not known for the quality of its reporting. I did not check carefully enough. When I mentioned it to my colleagues, they were like “why did you agree to an interview with them?” I began to worry. During the interview, I was upfront about my concern. I said that I did not want my statement to be shown in an alarmist way, that it was not a topic people should be too worried about. And it turned out to be a really good article! There’s a lesson there. You can have good experiences with these types of magazines and newspapers, and the upside is that you end up reaching a wider audience with a helpful message. But you have to make sure that it gets through clearly.

Do you follow a set of guiding principles when you communicate, either on social media or to news outlets?

I definitely do. My most important one is not to give political advice. It is fine for me to say “we need to talk about aerosols”, because we have to know about the dangers in restaurants and schools, for example. But I will not say “the government should shut all restaurants because of aerosol transmission”. These are not scientific decisions alone. These are problems that need to be weighed in on many avenues. I can offer a scientific thought about it, but what to do with it depends on a higher-level decision. At the end of the day, these are political decisions. In many ways, I’m glad it is not my job, because these are not easy calls to make. As a second principle, I try to stay grounded and calm during interviews. Getting too emotional often doesn’t help. Moreover, it is an easy way to be led into saying things you might regret later. Being angry or upset is often counterproductive.

Indeed, we do find quite a bit of anger and despair about the pandemic, from the public and experts alike. Yet, you seem to keep a cautiously optimistic tone in your messaging.

Because I try hard to do so! Of course, I do tweet negative things, because this pandemic is not always going very well. But I do my best not to post comments for the express purpose of saying how terrible things are. I try to be a more balanced voice, to end on a positive note, or to suggest a solution. It is more helpful than outlining how bad the situation is in an emotional way. It might sound a little arrogant, but at a certain point, you have to realize that you are enough of a public figure to decide who you should be in the public’s eyes. For me, it means that I don’t want to be in a position where it is my emotions speaking, rather than a more weighted and scientific mindset.

I suppose you also have to deal with a lot of aggressivity from some people, especially on social media?

I’ve been very strict in how I interact with users. I do not engage with people who are not being sincere — I am essentially talking about trolls. But I do engage as much as I can if I think people are being genuine. Even when I get a question that seems blunt, a little rude, or presumptuous, I keep in mind that many of us are scared. I try and err on the side of the benefit of the doubt: maybe they react in this way because they are worried. I do my best to respond with kindness, to pretend not to see the bluntness or the meanness. I begin with something like “Oh, that’s a great question, let me see if I can explain it to you”. You will generally get an answer, most often a sincere thank you. You can build some bridges there.

Some scientists are not that lucky and receive quite a bit of trolling and online abuse. How do you explain it?

I think that it is because I restrain myself. It is tempting to answer back to show how right you are. But I have found that it is not worth it. Trolls have more spare time than you, and you will only get angrier and angrier. If you ignore them, they usually go away. It is rather boring to tweet someone who never writes back, especially if your aim is just to be annoying.

In the end, how do you think the pandemic is going to affect the public perception of science?

I feel it will be positive. For example, our Nextstrain project was well known among infectious disease experts, but not beyond. Then in the spring, we had over 7,000% increase in web traffic. It is insane how popular it became. Before the pandemic, most of our visitors would never have shown interest in mutations and phylogenetics. It is fantastic. What people and governments are interested in, and what they are learning about will contribute to shaping the future of science. But it is our responsibility as scientists to help them make some sense of the science. On Nextstrain, people come looking and playing with these beautiful trees of sequences in different colors. It is awesome, but also dangerous. Let’s imagine you zoom in and find a sequence from Germany connected with France. You can make up stories about some French guy who went to Germany and brought the virus with him. It is very tempting. Of course, it is rarely true. It is a real challenge to prevent this kind of misinformation. As much as possible, you should try to educate people on how to read a phylogenetic tree. But you cannot prevent it all. On Twitter, I see so many people misinterpreting data about mutations. They often worry too much about it, while virus experts know this happens all the time. Communication is an ongoing job. We have to keep on explaining.