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.
Due to an error introduced during the production process, the Funding statement is incorrect. The correct Funding statement is: This work was funded by Centers for Disease Control, Department of Health, Taiwan, Republic of China. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Competing Interests: No competing interests declared.
