Until June 5th, the rate of imported cases has been stable in Germany. The first identified cases in Germany were confirmed on April 29 th , and until June 5 th a total number of 49 confirmed cases had been reported ( Figure S1 (A)). Of these 41 (84%) had a known travel history to Mexico, the United Kingdom or the USA; of the remaining 8 cases 7 had been contacts to one of the imported cases and for one case the source case was unknown but might have been related to contacts with travellers (airport worker). The average number of imported cases during this time period (38 days) corresponds to 1.1 cases per day, however, 28 of the 41 imported cases were reported during the 10 days prior to June 5 th (corresponding to 2.8 imported cases per day). We considered two different scenarios of case importation ( Figure S1 (B)): firstly, a constant number of imported cases per day (five or ten cases per day), and secondly, an exponentially growing number of imported cases limited to 120 imported cases per day. The exponential growth rate was determined by assuming an ''import-R0'' of 1.1 and the same generation time as for the transmission inside Germany.