Optimal lockdowns for COVID-19 pandemics: Analyzing the efficiency of sanitary policies in Europe.

Two main nonpharmaceutical policy strategies have been used in Europe in response to the COVID-19 epidemic: one aimed at natural herd immunity and the other at avoiding saturation of hospital capacity by crushing the curve. The two strategies lead to different results in terms of the number of lives saved on the one hand and production loss on the other hand. Using a susceptible-infected-recovered-dead model, we investigate and compare these two strategies.