Understanding immunity after typhoid vaccination

• Research type

  Research Study

• Full title

  A phase II, single-centre, randomised, single-blind, study to evaluate Vi-CRM197 against historical unvaccinated controls in a healthy adult challenge model, with a Vi-PS vaccine control arm.

• IRAS ID

  88094

• Contact name

  Andrew J Pollard

• Sponsor organisation

  Clinical Trials and Research Governance

• Eudract number

  2011-003653-26

• ISRCTN Number

  na

• Research summary

  This is a single-centre, randomised, participant-blind Phase 2 study that will use a challenge model of typhoid infection to evaluate a new conjugate typhoid vaccine, Vi-CRM197. The challenge model has been recently established by Oxford Vaccine Group, and involves an oral dose of S. Typhi chosen to achieve a typhoid infection attack rate of 60-75%. Healthy adult volunteers aged 18-60 will be recruited and randomised to one of 3 groups: Group 1, Vi-CRM197 Detailed Immunology; Group 2, Vi-CRM197 Standard Immunology; and Group 3 Vi-PS Detailed Immunology. Vi-PS is an established polysaccharide typhoid vaccine (Typherix), used as an active comparator to allow comparison between the immune response to vaccination with and without the protein conjugate CRM197. The difference between groups 1 and 2 is that group 2 will have fewer immunological investigations performed.28 days after vaccination with their assigned vaccine, participants will be challenged with oral S Typhi solution. The incidence and clinical features of typhoid infection in groups 1 and 2 will be compared to the same number of historical, unvaccinated, typhoid-challenged controls to demonstrate protective efficacy of the vaccine. Blood, stool and saliva samples taken at study visits will be explored to improve our understanding of the immune response to vaccination and challenge, to look for markers of protection against infection, and for new diagnostic markers of typhoid infection.

• REC name

  South Central - Oxford B Research Ethics Committee

• REC reference

  11/SC/0463

• Date of REC Opinion

  7 Dec 2011

• REC opinion

  Further Information Favourable Opinion