Published on in Vol 22, No 5 (2020): May
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/18718, first published
.
1 Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
2 Jiashan Prefectural Center for Disease Control and Prevention, Jiashan, China
*these authors contributed equally