Funding for this research was provided by:
National Basic Research Program of China (973 Program) (2016YFC1200902)
Text and Data Mining valid from 2019-04-03
Received: 18 September 2018
Accepted: 18 March 2019
First Online: 3 April 2019
Ethics approval and consent to participate
: The project was approved by the Ethical Committee of National Institute for Viral Disease Control and Prevention, China CDC.
: No applicable.
: The authors declare that they have no competing interests.
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