Why I Choose a PhD in Infectious Disease Modelling

I get this question a lot.

The short answer is that I chose to do a PhD in infectious disease modelling because I think research in that area can be incredibly useful for the world.

The long answer is complicated. I have wanted to write about this for a long time. However, each time I tried to write an answer, I delved excessively into the nuances of my decision-making. So here is a simplified version of the story.

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I always (since I was 14) wanted to do maths-related research, but I didn’t know in what area. My undergraduate personal statement said I wanted to do research in theoretical physics or mathematical biology. It became a self-fulling prophecy.

In the first days of my maths undergrad, it became obvious that pure mathematics wasn’t for me. Still, there was lots to choose from applied mathematics.

After my second year, I was incredibly lucky to do a summer research project in mathematical biology. Specifically, it was on population dynamics, an area of mathematical biology fairly similar (but distinct) to epidemiology. It was certainly successful, but it just didn’t click with me.

In my third year, I really enjoyed the theoretical physics courses. Continuing that route seemed the natural progression. After many cold emails, I got a research project one in theoretical cosmology, for the 2020 summer.

In the meantime, outside of my degree, I got interested in effective altruism (EA). A key idea in EA is to use reason and evidence to find the most effective ways of doing good. For example, you can have a big impact on the world with your career. This philosophy resonated a lot with me. However, at the time, I had other career plans (theoretical physics research). EA just stayed in the back of my mind.

Then COVID-19 came around. In January, I learnt I could use maths to model infectious diseases. In February, I had a lecture on the SIR model applied to COVID-19. In March, I found that my former lecturer (and now PhD supervisor) was advising the UK Government on pandemic response. Infectious disease modelling became a career option to consider.

I enjoyed my cosmology research project, but I also did some small ‘experiments’ to test if I liked infectious disease modelling.

I made a huge list of pros and cons for each option. But it boiled down to the following balance:

Theoretical physics would be essentially useless for the world, but I thought I’d enjoy it more than anything else. I thought could probably do fairly impactful work in disease modelling, but I had no clue whether I would enjoy it enough.

It was really hard to make the decision. Eventually, I recognized that my priority was (and still is) to maximise impact. Of course, there was a risk that I wouldn’t enjoy it. But I wouldn’t have known without trying it, and you can always drop out in the first months of a PhD…

So I applied for PhDs in infectious disease modelling. I’m now in my third year. Not a single day I’ve regretted that decision. I enjoy the field (especially the area I work in) much more than I thought I would. And it’s a topic for another post, but I still think this work can be very impactful.