Description
When COVID turned the world upside down in early 2020, health officials asked academic disease modelers like us for urgent guidance. Here we describe how we built Covasim (covasim.org), an agent-based COVID model, by using standard Python libraries like NumPy, Numba, and SciPy along with less common ones like Sciris (sciris.org). Covasim was created in a few weeks, an order of magnitude faster than the typical model development process, and achieves performance comparable to C++ despite being written in pure Python. It is now used by researchers and policymakers in more than a dozen countries.