Funding for this research was provided by:
Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (XMLX201813)
Capital’s Funds for Health Improvement and Research (2020-2-2102)
Received: 18 September 2020
Accepted: 10 March 2021
First Online: 1 April 2021
: The study was reviewed and approved by the Hospital Ethics Committee of Capital Institute of Pediatrics.
: Written consent was obtained
: The authors declare that they have no competing interests.