aInstitute of Social and Preventive Medicine, University of Bern, Switzerland
b900 and Family Clinics, Imperial College NHS Trust, London, UK
cPaediatric Haematology Oncology, Chris Hani Baragwanath Academic Hospital, University of the Witwatersrand, Johannesburg
dNational Cancer Registry, National Health Laboratory Service
eSchool of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
fMRC CTU, University College London Institute of Clinical Trials and Methodology
gPaediatric infectious Diseases Department, Great Ormond Street Hospital, London UK
Correspondence to Dr Anna Turkova, MRCPCH, MSc, MRC CTU, University College London Institute of Clinical Trials and Methodology, 90 High Holborn, London, UK. Tel: +442076704658; e-mail: a.turkova@ucl.ac.uk
