[1] Ctr Dis Control & Prevent, Natl Ctr Immunizat & Resp Dis, Atlanta, GA 30333 USA
[2] Ctr Dis Control & Prevent, Natl Ctr HIV AIDS Viral Hepatitis STD & TB Preven, Atlanta, GA USA
[3] Publ Hlth Agcy Canada, Ctr Infect Dis Prevent & Control, Immunisat & Resp Div, Ottawa, ON, Canada
[4] Publ Hlth Agcy Canada, Ctr Infect Dis Prevent & Control, Immunizat & Resp Infect Div, Ottawa, ON, Canada
[5] WHO, Initiat Vaccine Res, CH-1211 Geneva, Switzerland
[6] Univ Melbourne, Dept Obstet & Gynaecol, Royal Hosp Women, Dept Microbiol & Infect Dis, Melbourne, Vic, Australia