Estimate of the development of the epidemic reproduction number Rt from Coronavirus SARS-CoV-2 case data and implications for political measures based on prognostics

Sahamoddin Khailaie; Tanmay Mitra; Arnab Bandyopadhyay; Marta Schips; Pietro Mascheroni; Patrizio Vanella; Berit Lange; Sebastian Binder; Michael Meyer-Hermann

The latest Rt in the different federal states is compared and ranked in Figure 2E . Most federal states hit early on by the CoV-outbreak now exhibit rather low reproduction numbers, with the exception of Bayern. Interestingly, the federal states in Eastern Germany and Saarland, where the first cases were reported late, are spread all over the ranking. The largest reproduction number was found in Saarland. It appears that a late onset of cases also has the tendency to delay the reduction of the reproduction number. Figure 2A , a value for the transmission rate R1 corresponding to Rt values multiplied with 5/3, 4/3, 1, 2/3, and 1/3 (colors) is assumed for each of the 100 simulations in Figure 2 We next investigated what the now achieved reproduction number of around 1 implies for the future. Starting from the last state of the model, thus, including the complex distribution of individuals onto the different compartments of the model at this time, the simulation was continued for one year with the very same latest reproduction number in Germany (Figure 3 , black box plots) and in three federal states (Figure 4 , black box plots). The analysis for the other federal states can be found in the supplement and at (SIMM-group 2020). Keeping all measures in place in Germany induces a long-term increase of the number of infected cases ( Figure 3A , black). This is associated with a needed peak capacity of 6,000 hospital beds for CoV-patients in 2 weeks from now and about the same number of ICU beds 2 weeks later ( Figure 3B , black). Note that the number of needed ICUs is similar to the total number of hospitalized patients because the time spent in ICUs upon complications is longer. According to the model results, the number of deaths due to CoV would reach an order of 10,000 within the next 4 weeks (supplement and SIMM-group 2020).