Received: 17 January 2020
Accepted: 19 March 2020
First Online: 6 April 2020
Ethics approval and consent to participate
: Ethics approval and consent to participate were deemed not necessary for this study as all case-based data utilized in the study are routinely collected under the Robert Koch Institute’s legal mandate for national surveillance of infectious diseases in Germany, in accordance with the International Health Regulations Article 44. All data were fully anonymized before analysis.
: Not applicable.
: The authors declare that they have no competing interests.