Understanding Typhoid Disease After Vaccination

Inclusion criteria: * Male or female aged 18 - 60 years inclusive and in good health. * Have an abdominal ultrasound scan result documented demonstrating no evidence of gallbladder pathology. * Willing to allow their general practitioner and/or hospital consultant (if relevant) and the Health Protection Unit to be notified of participation in the study. * Agree to refrain from blood donation in the future if diagnosed with typhoid fever. * Be willing to have 24-hour contact with study staff during the four weeks post-challenge. Exclusion Criteria: * Have previously received any typhoid vaccine, been resident in a typhoid endemic country for over 6 months, been diagnosed with probable or confirmed typhoid infection or been challenged with Salmonella Typhi or enrolled in a typhoid challenge study. * Have any known or suspected impairment or alteration of immune function. * History of significant cardiovascular disease. * History of significant respiratory disease. * History of significant endocrine disorder. * History of significant renal or bladder disease. * History of biliary tract disease. * History of significant gastrointestinal disease. * History of significant neurological disease. * History of significant metabolic disease. * History of significant haematological diagnosis. * History of psychiatric illness requiring hospitalisation, current known or suspected drug or alcohol misuse. * History of significant infectious disease. * History of non-benign cancer. * Prese…