1. From the School of Public Health, University of the Western Cape, Bellville, Cape Town, South Africa (MEV); The Gade Institute, Section of Microbiology and Immunology; University of Bergen and Haukeland University Hospital, Bergen, Norway (HMSG); the Division of Dietetics, University of the Western Cape, Bellville, Cape Town, South Africa (ECS); the Medical Research Council, Cape Town, South Afri