Funding for this research was provided by:
Young Scientists Fund (81602851)
Excellent Young Talents of Health System in Shanghai (2017YQ043)
Text and Data Mining valid from 2019-11-02
Received: 26 March 2019
Accepted: 28 September 2019
First Online: 2 November 2019
Ethics approval and consent to participate
: The medical ethics committee of the Center for Endemic Disease Control at Harbin Medical University approved the study. Written informed consent was obtained from all parents or guardians.
: Not applicable.
: The authors declare that they have no competing interests.