Inferring COVID-19 spreading rates and potential change points for case number forecasts

Jonas Dehning; Johannes Zierenberg; Frank Paul Spitzner; Michael Wibral; Joao Pinheiro Neto; Michael Wilczek; Viola Priesemann

In order to simulate the general effect of different possible interventions on the spread of COVID-19 in Germany, we first focus on the initial phase of the outbreak where no serious mitigation measures were implemented. In the absence of interventions, an epidemic outbreak can be described by SIR models with constant spreading rate (Methods). In Germany, first serious interventions occurred around March 9 and affected the case reports with an observation delay, a combination of incubation period with median 5 − 6 days [32] and a test delay (time until doctor is visited plus test-evaluation time) that we assume to be about 2 days. Hence, we consider as initial phase the time period from March 1 to March 15 in order to infer central epidemiological parameters. We then model the effects of interventions as change points in the spreading rate (Methods) in order to simulate the effect of different possible interventions.