[1] London Sch Hyg & Trop Med, Maternal Adolescent Reprod & Child Hlth Ctr, Keppel St, London WC1E 7HT, England
[2] Univ Calif San Francisco, Dept Paediat, 550 16th St,Box 1224, San Francisco, CA 94158 USA
[3] London Sch Hyg & Trop Med, Fac Epidemiol & Populat Hlth, Keppel St, London WC1E 7HT, England
[4] MRC, Uganda Virus Res Inst, POB 49, Entebbe, Uganda
[5] MRC, LSHTM Uganda Res Unit, POB 49, Entebbe, Uganda
[6] UCL, Dept Neonatal Med, 235 Euston Rd, London NW1 2BU, England
[7] Makerere Univ, Ctr Excellence Maternal Newborn & Child Hlth, Sch Publ Hlth, New Mulago Hill Rd, Kampala, Uganda
[8] Karolinska Inst, Dept Publ Hlth Sci, SE-17177 Stockholm, Sweden
[9] London Sch Hyg & Trop Med, Fac Publ Hlth & Policy, 15-17 Tavistock Pl, London WC1E 7HT, England
[10] MRC, Unit Gambia LSHTM, POB 273, Fajara, Gambia