[1] St Thomas Hosp, Evelina Childrens Hosp, Dept Gen Paediat, London SE1 7EH, England
[2] Carlos III Hosp, Dept Paediat, Paediat Infect Dis & Trop Dis Unit, Madrid, Spain
[3] Univ London Imperial Coll Sci Technol & Med, Div Infect Dis, Paediat Sect, London, England
[4] Bambino Jesu Hosp, Paediat Infect Dis Unit, Rome, Italy
[5] Dr Victor Babes Hosp Infect & Trop Dis, HIV Dept, Bucharest, Romania
[6] Med Univ Warsaw, Infect Dis Hosp, Childrens Infect Dis Dept, Warsaw, Poland
[7] Hosp Gen Gregorio Maranon, Dept Paediat, Infect Dis Sect, Madrid, Spain
[8] Univ Amsterdam, Acad Med Ctr, Emma Childrens Hosp, Dept Pediat Hematol Immunol & Infect Dis, NL-1105 AZ Amsterdam, Netherlands
[9] Univ London, Div Clin Sci, London, England
[10] Univ London, Vaccine Inst, London, England