Wang, Guojie
Xu, Jiying
Huang, Bin
Gao, Sanyou
Zhuang, Yan
Wang, Kan
Zhang, Yanqiu
Jiang, Jianguo
Article History
Received: 5 February 2020
Accepted: 17 June 2020
First Online: 8 July 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Henan Provincial Centre for Disease Control and Prevention. All data were de-identified and confidentiality of data was maintained.
: Not applicable.
: The authors declare that they have no competing interests.