About the Authors

Jun Cheng

Affiliation Chinese Center for Disease Control and Prevention, Beijing, China

Lixia Wang

Affiliation Chinese Center for Disease Control and Prevention, Beijing, China

Hui Zhang

Affiliation Chinese Center for Disease Control and Prevention, Beijing, China

Yinyin Xia

xiayinyin@chinatb.org

Affiliation Chinese Center for Disease Control and Prevention, Beijing, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: JC. Performed the experiments: JC LXW HZ YYX. Analyzed the data: JC LXW HZ YYX. Contributed reagents/materials/analysis tools: JC LXW HZ YYX. Wrote the paper: JC. Made final approval of manuscript to be published: LXW HZ. Revised manuscript critically: YYX.