Transparent Covid-19 prediction

We present a very simple and transparent method to interpret time series of confirmed Covid-19 cases. Roughly speaking, the analysis of weekly new infections for each day is a tool for the definition and early detection of the turning point of the epidemic. In Italy, the growth of Covid-19 activity was overcome one week ago, Austria and Switzerland followed suit. This note emphasizes the crucial delay of two weeks between infection and listing of infection in a central database. Our estimates of the time course of Covid-19 activity and reproduction rates can reduce the information gap by several days. We show that Spain and Germany are already beyond the turning point. In general the estimated reproduction rates become undercritical a short time after the main lockdown measures, and the Covid-19 activity starts to decrease afterwards. This note gives a very optimistic outlook for all regions which have taken strict containment measures.