Affiliation: | National Institute for Communicable Disease Control and Prevention, Beijing, People’s Republic of China (H. Zhou, L. Xu, Z. Shao); ;State Key Laboratory for Infectious Disease Prevention and Control, Beijing (H. Zhou, Z. Shao); ;Guangxi Center for Disease Control and Prevention, Nanning, People’s Republic of China (W. Liu, L. Deng, Q. Deng, J. Zhuo) |