[1] Guangxi Med Univ, Dept Epidemiol & Biostat, Sch Publ Hlth, Nanning, Guangxi Zhuang, Peoples R China
[2] Prince Songkla Univ, Epidemiol Unit, Fac Med, Hat Yai, Thailand
[3] Guangxi Ctr Dis Control & Prevent, Inst Vaccinat, Nanning, Guangxi Zhuang, Peoples R China