Viral spreading in a small world
As we write this, the world is in the midst of a pandemic, the worst of at least 100 years, and the first in the era of widespread social connectivity. Humanity has certainly overcome pandemics before. The Black Plague, for example, decimated a significant proportion of the world’s population, and the Spanish flu pandemic of 1918 – our first encounter with the H1N1 virus – killed more than 40 million people worldwide over a period of just under a year, yet epidemiologists the world over are bracing for the next “big one” and wondering if the world can survive it. But why? Surely today we are far more aware of how viruses spread, of the role that hygiene plays in their containment, of how to sequence viral RNA and produce vaccines or antiviral drugs in record time? Well, it turns out that with the leaps in technology that have come since the Third Industrial Revolution, we now live in a world that is more connected than ever before and with this global connectivity comes an unprecedented risk of global spread of disease. As the world scrambles to contain outbreaks like Ebola in 2014, or Covid-19 in 2020, the role of doctors, virologists, and even politicians are intuitively obvious. But what could mathematicians, or more precisely applied mathematicians, possibly contribute to this calculus? In a word: Modelling.