1. Department of Epidemiology and Biostatistics, School of Public Health, Peking University, China (X.H., K.M., W.C., J.L., C.Y., T.H., D.S., C.L., Y.P., W.G., L.L.).
2. Qingdao Center for Disease Control and Prevention, China (Z.P.).
3. Zhejiang Center for Disease Control and Prevention, Hangzhou, China (M.Y.).
4. Jiangsu Center for Disease Control and Prevention, Nanjing, China (H.W.).
5. Sichuan Center for Disease Control and Prevention, Chengdu, China (X.W.).
6. Heilongjiang Center for Disease Control and Prevention, Harbin, China (Y.L.).