1 Vaccines and Immunity Theme, Medical Research Council (MRC) Unit - The Gambia, Banjul, The Gambia.
2 Department of Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada.
3 Centre for International Health, Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
4 Vaccines and Immunity Theme, Medical Research Council (MRC) Unit - The Gambia, Banjul, The Gambia, Centre for International Child Health, Academic Department of Paediatrics, St. Mary's Campus, Imperial College London, London, United Kingdom. <email></email>, e-mail: <email>[email protected]</email>, Email: [email protected].