Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The affiliation for the seventh author is incorrect. The correct affiliation is: Institute of Disease Control and Prevention, Chinese Academy of Military Medical Sciences, Beijing, P.R. China
