Investigating Enteric Fever - Salmonella Typhi and Paratyphi Challenge Study

Exclusion Criteria

• •History of significant organ/system disease that could interfere with study conduct or completion.
• •Have any known or suspected impairment of immune function, alteration of immune function, or prior immune exposure that may alter immune function.
• •Moderate or severe depression or anxiety as classified by the Hospital Anxiety and Depression Score at screening or challenge that is deemed clinically significant by the study investigators.
• •Weight 50kg or less.
• •Presence of implants or prosthesis.
• •Have previously received any typhoid vaccine
• •Any contraindication to elective upper GI endoscopy.
• •More than one non-study related upper GI endoscopy within the last year.
• •Anyone taking long-term medication that may affect symptom reporting or interpretation of the study results.
• •Contra-indication to taking ciprofloxacin, azithromycin, trimethoprim/ sulfamethoxazole and/or beta lactam antibiotics.
• •Female participants who are pregnant or lactating.
• •Female participants who are unwilling to ensure that they or their partner use effective contraception one month prior to challenge and continue to do so until two negative stool samples, a minimum of three weeks after completion of antibiotic treatment, have been obtained.
• •Full-time, part-time or voluntary occupations involving clinical or social work with direct contact with young children (defined as those attending pre-school groups or nursery or aged under 2 years); clinical or social work with direct contact with highly susceptible patients or persons in whom typhoid or paratyphoid infection would have particularly serious consequences e.g. the elderly or infirm.
• •Full time, part time or voluntary occupations involving commercial food handling.
• •Close household contact with young children (defined as those attending pre-school groups, nursery or those aged less than 2 years), individual(s) who is (are) immunocompromised, scheduled elective surgery or other procedures requiring general anaesthesia during the study period.
• •Participants who have participated in another research study involving an investigational product that might affect risk of typhoid or paratyphoid infection or compromise the integrity of the study within the 30 days prior to enrolment .
• •Detection of any significantly abnormal results from screening investigations.
• •Inability to comply with any of the study requirements.
• •Any other social, psychological or health issues which, in the opinion of the study investigator, may put the participants or their contacts at risk because of participation in the study, adversely affect the interpretation of the primary endpoint data, or impair the participant's ability to participate in the study.
• •Having been resident in an enteric fever endemic country for six months or more.