Published on in Vol 8, No 4 (2022): April
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/29906, first published
.
1 Chinese Center for Disease Control and Prevention, Beijing, China
2 National Center for Women and Children's Health Chinese Center for Disease Control and Prevention, Beijing, China
3 Capital Institute of Pediatrics, Beijing, China
*these authors contributed equally