Funding for this research was provided by:
Harvard T.H. Chan School of Public Health (5105921_263681)
anonymous donor (5105921_263681)
Received: 2 October 2020
Accepted: 25 January 2021
First Online: 18 February 2021
Ethics approval and consent to participate
: Necessary ethical clearance was granted by ethical review committee of Aga Khan University, Karachi, Pakistan (4964-Ped-ERC-17). Written consent was obtained from the participants prior to enrollment.
: Not applicable.
: The authors declared that they have no competing interests.