Covid-19 lockdowns came by surprise in March 2020, and one month later there was still no clear exit path. While scientists around the world were focusing on SIR models to predict the propagation of the virus, and its ensuing consequences on health systems, we proposed an alternative approach to tackle the pandemic based on the following imperatives: (1) integrate a network aspect (absent in most SIR models); (2) integrate the protection of the economy (absent in most discussions); (3) remain as simple and graphical as possible, so as to be understood by decision-makers, and thus remain applicable. Our model soon made it to the French and Spanish governments, who adopted it as an exit strategy on 28 April 2020. Subsequently, many other countries followed our approach throughout the crisis, including Italy, Chile, and Australia.
In this talk, I will start by presenting our model, then discuss its path from applied mathematics to policy implementation, and will end with the lessons learned.