[1] Univ Western Australia, Sch Paediat & Child Hlth, Perth, WA 6009, Australia
[2] Telethon Inst Child Hlth Res, Vaccine Trials Grp, Perth, WA, Australia
[3] Royal Hosp Women, Dept Microbiol & Infect Dis, Melbourne, Vic, Australia
[4] Univ Melbourne, Dept Obstet & Gynaecol, Melbourne, Vic, Australia
[5] Univ Cambridge, Dept Pathol, Cambridge CB2 1QP, England
[6] La Trobe Univ, Australian Res Ctr Sex Hlth & Soc, Melbourne, Vic, Australia
[7] Royal Hosp Women, Oncol & Dysplasia Unit, Melbourne, Vic, Australia