Double Power Law for Covid-19: Prediction of New Cases and Death Rates in Italy and Spain

Osherovich, Vladimir A.; Fainberg, Joseph; Osherovich, Lev Z.

The novel coronavirus SARS-CoV-2 appeared at the end of 2019, spreading rapidly and causing a severe respiratory syndrome (COVID-19) with high mortality. Until a vaccine or therapy is found, the most effective method of prophylaxis has been to minimize transmission through mandatory social distancing and restriction of all but essential economic activity. A key question facing policy makers and individuals is when to resume economic and social activity in the face of persistent community transmission of SARS-CoV-2. To help address this question, we have developed a mathematical model of transmission and mortality of COVID-19 in countries that have implemented stringent social distancing measures. Using data from Italy, Spain, Switzerland and Germany on SARS-CoV-2 transmission, active caseload and mortality, we model the rapid rise and slow decay ("long tail") of the COVID-19 pandemic using a first order nonlinear differential equation. The prognostic utility of our model is validated by strong correspondence between predicted and prospectively observed data up to eight weeks after curve fitting. This Double Power Law model can be applied to other countries as a predictive tool to inform policy decisions concerning social distancing.