Safety and Immunogenicity of a Vi-DT Typhoid Conjugate Vaccine
Condition: Typhoid
MeSH terms: Typhoid Fever
Study type: Interventional
Phase: Phase 1

Summary: 
      This is a Phase I, Randomized, observer-blinded, age de-escalating study.

      The study objectives are:

        1. To evaluate the safety of 25 μg of Vi-DT typhoid conjugate vaccine administered at 0 and
           4 weeks.

        2. To assess the immunogenicity of 25 μg of Vi-DT typhoid conjugate vaccine administered at
           0 and 4 weeks.

        3. To compare the safety and immunogenicity of Vi-DT and Vi-Polysaccharide typhoid
           vaccines.
    

Detailed description: 
      This study will be carried out in healthy adults and children at a single site. Subjects will
      be stratified according to age.

      The study procedure is as follows:

      Visit 1 (day-1 to -7): Screen participants by medical history, physical examination and lab
      investigations. Collect blood for safety and immunogenicity assessments.

      Visit 2 (day 0): Enroll, randomize and administer first dose of vaccine to eligible
      participants

      Visit 3 (day 3): Assess participant safety by medical history and physical examination

      Visit 4 (day 7): Record solicited adverse reaction 7 days post vaccination, and collect blood
      for safety lab assessments.

      Visit 5 (day 28): Assess participant safety, collect blood for immunogenicity assessments,
      and administer second vaccine dose

      Visit 6 (day 31): Participants safety will be assessed by medical history and physical
      examination

      Visit 7 (day 35): Record solicited adverse reaction 7 days post second vaccination.

      Visit 8 (day 56): Collect blood for immunogenicity assessments, assess participant safety,
      and fill in study completion form in the absence of any safety concern.

      This study is observer-blind: vaccine administrator and vaccine safety evaluator will be two
      distinct persons to avoid bias of safety assessment. Trial staff other than the vaccine
      administrator.
    

Intervention name(s): Vi-DT; Typhim Vi®; VAXIGRIP®
Intervention type(s): Biological; Biological; Biological
Intervention description(s): Manufacturer: SK Chemicals Co., Ltd. Ingredient: Purified Vi-polysaccharide conjugated to diphtheria toxoid Dose: 0.5 mL/Vial; Manufacturer: Sanofi Pasteur Ingredient: Purified Vi-polysaccharide Appearance: colourless liquid Dose: 0.5mL/vial; Dose: Single injection, participants 6-35 months of age will receive 0.25 ml (half a dose), participants 36 months of age and older will receive 0.5ml (full dose)
*Participants less than 9 years of age, who have not been vaccinated for flu before, will receive a second dose of flu-vaccine after the last follow-up visit of last participant in their age cohort.
Other intervention name(s): Vi-DT typhoid conjugate vaccine
Intervention MeSH terms: Vaccines
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Typhoid conjugate vaccine; Vi-DT; Safety; Immunogenicuty