At the time of writing on February 25th we already know quite a lot about the Covid19 and, at the same time, many uncertainties remain. Limiting oneself to official and authoritative scientific sources, we have already learned that the virus attacks almost exclusively adults; that it is fatal mainly in the case of older people and/or if they suffer additional pathologies (smoking, cancers, diabetes, hypertension…) and is otherwise less dangerous than the annual flew epidemic with a low rate of fatalities. Among still unknown factors remain the seasonality of the virus (will it disappear in spring?), the delay for providing a vaccine (10-18 months?) or the length of the incubation period (14-27 days?). Fundamental is the correctness of the data…