Mei Dong a, Ming Luo a, Aihua Li a, Hui Xie a, Cheng Gong a, Juan Du b, Xinrui Wang b, Maozhong Li a, Xue Wang a, Yiting Wang a, Haiyan Zhang c, Xiaoxing Yang d, Wei Cai e, Hongjun Li f, Wenzeng Zhang g, Lijun Ren h, Qing-Bin Lu b, ⁎
, Fang Huang a, ⁎ 
a Institute for immunization and prevention, Beijing Center for Disease Control and Prevention, Beijing Research Center for Preventive Medicine, No.16 Hepingli Middle Street, Dongcheng District, Beijing, PR China
b Department of Laboratorial Science and Technology, School of Public Health, Peking University, No.38 XueYuan Road, Haidian District, Beijing, PR China
c Institute for Infectious Diseases and Endemic Diseases Prevention and Control, Dongcheng Center for Disease Control and Prevention, No.5 Beibing Masi Hutong, Dongcheng District, Beijing, PR China
d Institute for Infectious Diseases and Endemic Diseases Prevention and Control, FengTai Center for Disease Control and Prevention, Kandan Science and Technology Industrial Park, Fengtai District, Beijing, PR China
e Institute for Infectious Diseases and Endemic Diseases Prevention and Control, Haidian Center for Disease Control and Prevention, No.5 Xibeiwang, 2nd Street, Haidian District (Health Building), Beijing, PR China
f Institute for Infectious Diseases and Endemic Diseases Prevention and Control, Tongzhou Center for Diseases Prevention and Control, No.1 North Street, Luhe Middle School, Tongzhou District, Beijing, PR China
g Institute for Infectious Diseases and Endemic Diseases Prevention and Control, Shunyi District Centers for Disease Control and Prevention, No. 66 Shunkang Road, Shunyi District, Beijing, PR China
h Institute for Infectious Diseases and Endemic Diseases Prevention and Control, Shijingshan Center for Disease Control and Prevention, No. 6 Stadium South Road, Shijingshan District, Beijing, PR China