[1] Hop Univ Necker Enfants Malad, APHP, Reference Ctr Sickle Cell Dis, Dept Pediat, Paris, France
[2] Muhimbili Univ Hlth & Allied Sci, Dept Haematol & Blood Transfus, Dar Es Salaam, Tanzania
[3] Nuffield Dept Med, Oxford, England
[4] Kings Coll Hosp NHS Fdn Trust, Kings Hlth Partners, Dept Paediat Haematol, London SE5 9RS, England