Projecting the Spread of COVID19 for Germany

Jean Roch Donsimoni; Rene Glawion; Bodo Plachter; Klaus Waelde

This section describes what we know quantitatively about the spread of reported infections. We start with Hubei and its capital Wuhan in China. We afterwards look at South Korea and very brie ‡y at Japan. We focus on the evolution of the number of individuals that were ever reported to be sick during the current epidemic. This number, by construction, can only rise. We chose Hubei and South Korea as the epidemics seem to come to an end in these countries. Given the huge uncertainty about long-run infection rates and individual risk to get sick after an infection with CoV-2, we consider the long-run ratios of sick reported individuals to the overall population a benchmark that allows us to judge the credibility of our predictions for Germany. We are aware that we compare very di¤erent countries with very di¤erent cultural and political habits and medical systems. For reference, we also look at a cross section of infections for European countries. See the appendix for a description of data sources. 6 Hubei Since the onset of the outbreak in the Hubei province in China, the number of con…rmed cases has risen dramatically, peaking at 67,801 (WHO Situation Reports, 2020). 7 Reporting began in January 2020 and we note that in mid-February, the WHO changed its classi…cation methodology by reporting both clinically and lab con…rmed cases rather than only lab con…rmed cases. In terms of cumulative numbers, the total reported cases of infected individuals rose 4 Eichenbaum et al. (2020) study the e¤ects of the CoV-2 epidemic on economic decisions of households. They emphasize the household decisions to reduce labour supply exacerbate the recessionary e¤ects of the epidemic. They apply their model to the US. Barro et al. (2020) employ mortalities and economic consequences of the "Spanish Flu" to provide estimates of the world wide consequences of COVID19. They do not o¤er a detailed projection for Germany. The costs for Germany are estimated by Dorn et al. (2020) . Atkeson (2020) provides esitmates of economic consequences of COVID19 for the US. 5 When working with continuous states like e.g. wealth or labour income, partial di¤erential equations result. See e.g. Bayer and Wälde (2010a) , Achdou et al. (2020) , Kaplan et al. (2018) or Khieu and Wälde (2020) . 6 Note that all …gures below are as of 26 March 2020 and come from the Johns Hopkins University dataset from Dong et al. (2020) . 7 There are attempts to correct supposedly under reported numbers from China by employing South Korea as a benchmark country (Lachmann, 2020). continuously since January, since there have been continuous in ‡uxes of new cases and very little communication about individuals transitioning back to being healthy.