Received: 16 October 2020
Accepted: 18 February 2021
First Online: 25 February 2021
Ethics approval and consent to participate
: It was performed according to the strengthening the reporting of observational studies in epidemiology (STROBE) guideline and was approved by the First Affiliated Hospital of Chongqing Medical University Biomedical Research Ethics Committee before starting the study (IRB approval number 2020–559). And all patients, including the parents of the patient younger than 18 years old, gave written informed consent to their participation in the study, which followed the ethical guideline of the Declaration of Helsinki.
: Not applicable as there is no identifiable material in this manuscript.
: The authors declare that they have no competing interests.