Received: 24 May 2019
Accepted: 25 June 2020
First Online: 3 July 2020
Ethics approval and consent to participate
: Ethical approval and consent to participate was not required for this retrospective study, since all samples were sent to out laboratory for routine laboratory analysis for <i>B. pertussis</i> and afterwards anonymised for statistical evaluation.
: Not applicable.
: The authors declare that they have neither financial nor non-financial competing interests.