Typhoid fever
Conditions
Interventions
This study is a randomised, observer- and participant-blind, parallel-group comparative study in children in Kathmandu Valley, Nepal, who were previously vaccinated with Vi-CRM197 typhoid conjugate va
Sponsors
University of Oxford
Eligibility
Sex/Gender
All
Age
4 Years to 6.5 Years
Inclusion criteria
Inclusion criteria: Children living in Kathmandu Valley, Nepal, who: 1. Previously received a single dose of Vi-CRM197 typhoid conjugate vaccine at 15–20 months of age through the national immunisation programme or catch-up campaign 2. Are at least 4 years post-primary vaccination at enrolment (typically aged 5–6.5 years) 3. Have verifiable documentation of prior vaccination 4. Are in good health on the day of vaccination according to the attending doctor 5. Have a parent/legal guardian willing and able to provide informed consent and support study follow-up 6. Live within the study catchment area
Exclusion criteria
Exclusion criteria: 1. Unable to provide verifiable documentation of prior Vi-CRM197 vaccination 2. Known allergy to any vaccine component 3. Any medical or social condition that may prevent compliance with study procedures or follow-up 4. Known congenital or acquired immunodeficiency that could affect vaccine responses 5. Planning to move away from the study catchment area during follow-up 6. Temporary exclusion at the time of vaccination due to reported fever within the previous 24 hours or receipt of another vaccination within the previous 48 hours
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Anti-Vi IgG and IgA antibody responses measured using laboratory immunoassays (ELISA) to assess anti-Vi IgG and anti-Vi IgA antibody concentrations in plasma samples at Day 28 post-booster vaccination | — |
Secondary
| Measure | Time frame |
|---|---|
| Anti-Vi IgG and IgA antibody responses measured using laboratory immunoassays (ELISA) to assess anti-Vi IgG and anti-Vi IgA antibody concentrations in plasma samples at 6 and 18 months;Vaccine safety measured using data collected on the proportion of participants developing all adverse events within the first 7 days post-vaccination, and serious adverse events at 7 days, 28 days and 6 months post booster vaccination;The incidence of typhoid and paratyphoid disease in the boosted participants measured using blood culture confirmed cases of typhoid or paratyphoid fever from passive surveillance in participants at throughout the study period | — |
Countries
Nepal
Contacts
Public ContactAndrew Pollard
Outcome results
None listed