Yu, Guimei
Wang, Jiu
Liu, Lei
Li, Yun
Zhang, Yi
Wang, Songsong
Funding for this research was provided by:
Medical and Health Technology Development Plan of Shandong Province (1)
Article History
Received: 17 December 2019
Accepted: 25 March 2020
First Online: 3 April 2020
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the Yantai CDC.
: Not applicable.
: The authors declare that they have no competing interests.