Modeling the first wave of the COVID-19 pandemic in the Lombardy region, Italy, by using the daily number of swabs

The daily fluctuations in the released number of Covid-19 cases played a big role both at the beginning and in the most critical weeks of the outbreak, when local authorities in Italy had to decide whether to impose a lockdown and at which level. Public opinion was focused on this information as well, to understand how quickly the epidemic was spreading. In this work, we propose a nonlinear asymmetric diffusion model, which includes information on the daily number of swabs, to describe daily fluctuations in the number of confirmed cases in addition to the main trend of the outbreak evolution. The proposed model is compared with alternative model structures in the application to data of the Lombardy region.