John Anthony Scott is Professor of Epidemiology at the University of Oxford. He has developed an international reputation in key areas of global health, invasive bacterial diseases, pneumonia and childhood vaccines. He provided the first comprehensive description of pneumonia aetiology in adults. He set up the largest population surveillance system in Africa and used it to define the epidemiology of bacteraemia in children. His seminal studies of the epidemiology of invasive bacterial infections in children defined the biology of the disease and its public health importance. He has established an international surveillance network for pneumococcal disease in East Africa and designed and executed a global multi-site study of pneumonia aetiology in children.