Received: 4 April 2019
Accepted: 14 August 2019
First Online: 22 August 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Institutional Review Board of Vinmec International Hospital on March 10, 2014. The reference number for the ethics committee is 381/2015/QD-VINMEC. The committee evaluated the ethical aspects of the study in accordance with The World Medical Association’s Declaration of Helsinki. The study was explained in detail to parents of the participants. Parental written informed consent was obtained well before patient enrollment in all cases.
: Parental written informed consent was obtained well before patient enrollment in all cases. This consent included their agreement to the publication of indirect identifiers for patients, such as age and gender.
: The authors declare that they have no competing interests.