Article History
Received: 14 October 2019
Accepted: 14 January 2020
First Online: 27 January 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The sampling was approved by the local ethics commission (Kantonale Ethikkommission Zürich, KEK), declaration of no objection no. 24-2015.
: Body fluids and buccal swabs were collected from volunteers with their oral informed consent.