[1] Univ Melbourne, Melbourne Sexual Hlth Ctr, Sch Populat Hlth, Melbourne, Vic 3053, Australia
[2] Pacific Adventist Univ, Port Moresby, Papua N Guinea
[3] Univ Papua New Guinea, Sch Med & Hlth Sci, Ndc, Papua N Guinea
[4] Pacific Int Hosp, Port Moresby, Papua N Guinea
[5] Univ Melbourne, Dept Publ Hlth, Key Ctr Womens Hlth Soc, Melbourne, Vic 3053, Australia
[6] Univ New S Wales, Natl Ctr HIV Epidemiol & Clin Res, Sydney, NSW 2052, Australia