Funding for this research was provided by:
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics (SKLVD2018KF001, SKLVD2018KF002)
Received: 28 March 2019
Accepted: 25 August 2019
First Online: 18 September 2019
Ethics approval and consent to participate
: This effort of outbreak control and investigation was part of CDC’s routine responsibility in Changsha City; therefore, institutional review and informed consent were waived by Medical Ethics Committee of Changsha Center for Disease Control and Prevention on the following grounds: (1) all data analyzed were anonymized.; (2) neither medical intervention nor biological samples were involved; (3) study procedures and results would not affect clinical management of patients in any form.
: Not applicable.
: No authors declare a conflict of interest.