1. W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
2. Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
3. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
4. Research Centre for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institute, Copenhagen, Denmark
5. Bandim Health Project, Indepth Network, Bissau, Guinea-Bissau