Funding for this research was provided by:
Research Foundation of the Capital Institute of Pediatrics (QN-2016-09, PY-2020-05)
Received: 23 January 2020
Accepted: 7 July 2020
First Online: 13 July 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the Capital Institute of Pediatrics. Written consent forms were obtained from the participants’ guardians before collecting the pharyngeal swab samples, and the anonymity of the participants was guaranteed.
: Not applicable.
: The authors have indicated they have no competing interests.