Funding for this research was provided by:
national institute of public health - national institute of hygiene (3/EM/2016)
Received: 25 June 2021
Accepted: 22 November 2021
First Online: 7 December 2021
: The study was approved by the local bioethics committee at the Centre of Postgraduate Medical Education (Research Bioethics Committee No. 39/PB/2014), Warsaw, Poland. Prior to taking the swab, all the patients gave a voluntary informed consent to their participation after being adequately informed of the study aim, data processing and the use of the data in line with the Declaration of Helsinki. The participation was voluntary, and the participants could refuse to participate.
: Not applicable.
: The authors declare that they have no competing interests in this work.