[1] Guangdong Med Univ, Dept Prevent Med, Dongguan, Peoples R China
[2] Guangdong Med Univ, Maternal & Child Res Inst, Women & Childrens Hosp, Shunde Dist Maternal & Child Hlth Hosp, Foshan, Peoples R China
[3] Guangdong Med Univ, Sch Clin, Dongguan, Peoples R China
[4] Guangdong Med Univ, Dept Epidemiol & Biostat, Dongguan, Peoples R China
[5] Shenzhen Ctr Dis Control & Prevent, Dept Immunizat Program, Shenzhen, Peoples R China
[6] Dalang Town Community Hlth Serv Ctr, Publ Hlth Off, Dongguan, Peoples R China
[7] Guangdong Med Univ, Microbiol & Immunol, Dongguan, Peoples R China
[8] Southern Med Univ, Neonatal Dept, Shenzhen Maternal & Child Hlth Hosp, Shenzhen, Peoples R China