Article History
Received: 31 July 2020
Revised: 30 October 2020
Accepted: 4 November 2020
First Online: 10 November 2020
Compliance with ethical standards
:
: none to declare.
: The study was registered at Pan African Clinical Trials Registry (PACTR) ExternalRef removed with trial number PACTR201907742119058.
: Local ethics committee of Faculty of Medicine, Tanta University approved the study. The study is in accordance with the ethical standards of institutional research committee and with the 1964 Helsinki declaration and its later amendments.
: an informed consent was obtained from the parents of all subjects of the study before enrollment.
: All the authors transfer, assign, or otherwise convey all copyright ownership, including any and all rights exclusively to the journal, in the event that such work is published by the journal.
: Available when required.
: not applicable.