[1] Queen Mary Univ London, Blizard Inst, London, England
[2] Zvitambo Inst Maternal & Child Hlth Res, Harare, Zimbabwe
[3] South African Med Res Council, Cape Town, South Africa
[4] Univ Pretoria, Dept Paediat, Hatfield, South Africa
[5] Univ Liverpool, Dept Mol & Clin Pharmacol, Liverpool, Merseyside, England
[6] Makerere Univ, Infect Dis Inst, Coll Hlth Sci, Kampala, Uganda
[7] Inst Pasteur, EPVO Unit, Paris, France
[8] Imperial Coll London, Sect Virol, London, England
[9] WHO, Dept Maternal Newborn Child & Adolescent Hlth, Geneva, Switzerland
[10] Columbia Univ, ICAP Columbia, Mailman Sch Publ Hlth, New York, NY USA
[11] Columbia Univ, Vagelos Coll Phys & Surg, New York, NY USA
[12] Imperial Coll Healthcare NHS Trust, Dept Paediat, London, England
[13] Univ Montpellier, CHU Montpellier, Pathogenesis & Control Chron Infect, INSERM,Etab Francais Sang, Montpellier, France