About the Authors

Zhifang Wang

zfwang@cdc.zj.cn

Affiliation Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China

Yaping Chen

Affiliation Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China

Jinren Pan

Affiliation Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: ZW. Performed the experiments: ZW. Analyzed the data: ZW YC JP. Contributed reagents/materials/analysis tools: ZW YC JP. Wrote the paper: ZW.