Received: 7 October 2019
Accepted: 16 January 2020
First Online: 21 January 2020
Ethics approval and consent to participate
: The final protocol was approved by the ethics committee of the University of Heidelberg, Heidelberg, Germany (S-296/2019). Written informed consent will be obtained from each participant before entering the trial.
: Not applicable.
: The authors declare that they have no competing interests.