Typhoid fever Infections and Infestations Typhoid fever
Conditions
Interventions
This is a prospective cohort study, alongside the continuation of a community surveillance study, which will include conducting healthcare facility-based passive surveillance for typhoid fever in vacc
Sponsors
University of Oxford
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: Prospective cohort study: 1. Individuals who were enrolled in the TyVAC trial 2. Parent/legal guardian/participant 18 years and older give informed consent 3. Parent/legal guardian/participant 18 years and older confirms that their child/they will be willing and able to comply with study requirements Community surveillance: 1. Individuals presenting to the healthcare facility with a history of =2 days of fever, and/or a recorded temperature =38.0°C 2. Individual willing and competent to give informed consent if =18 years or the parent/legal guardian if participant <18 years. Assent will be sought from children 7 years of age or older 3. Able to comply with study requirements Immunogenicity: 1. Children enrolled and randomized in the TyVAC trial who have received Vi-TCV either in early or late cohorts 2. Parent/legal guardian is willing and competent to provide informed consent. If the participant is 7 years of age or older, assent will also be sought. If the participant is 18 years or older, consent will be sought from them. 3. Parent/legal guardian confirms that their child will be willing and able to comply with study requirements Immunogencity – Vi-TCV & Vi-CRM197: 1. Children enrolled and randomized in the TyVAC trial who have received both Vi-TCV and Vi-CRM197 OR who have received the Vi-CRM197 only 2. Parent/legal guardian is willing and competent to provide informed consent. If the participant is 7 years of age or older, assent will also be sought. If the participant is 18 years or older, consent will be sought from them 3. Parent/legal guardian confirms that their child will be willing and able to comply with study requirements Census: 1. Head of household/key informant is willing and competent to give informed consent for the participation of the household in the study 2. Head of household/key informant is male or female, aged 18 years or above 3. Household is within the census area Qualitative Component: For FGDs or IDIs to explore the perception of the overall study: 1. Parents/guardians of the vaccinated children or participants of TyVAC Nepal who received vaccination and are =18 years old who consent to participate 2. Tole health promoters willing to participate 3. Key-informant interview/in-depth interview with the community leaders In-depth interview/FGD regarding blood draw during passive surveillance visit: 1. Vaccinated children =18 years along with adults presenting with fever at the passive surveillance clinic at Patan Hospital who are asked for a blood draw and those who consent for IDI will be included 2. Parents/guardians of vaccinated children less than 18 years presenting with fever at the passive surveillance clinic at Patan Hospital and those who consent for IDI will be included 3. Parents/guardians of children or participants themselves (=18 years old) who present with fever at passive surveillance clinics and are asked for a blood draw will be included in the FGD if they provide consent for FGD 4. Research medical officers and r
Exclusion criteria
Exclusion criteria: Prospective cohort study: 1. Consent withdrawn from the TyVAC trial 2. Did not give consent for contact for future studies in the TyVAC trial Immunogenicity: 1. Consent withdrawn for immunogenicity in the TyVAC trial 2. Deemed clinically unsuitable by the survey team (e.g. terminally ill) Immunogenicity – Vi-TCV & Vi-CRM197: 1. Consent withdrawn for immunogenicity in the TyVAC trial 2. Deemed clinically unsuitable by the survey team (e.g. terminally ill) Census: 1. Unable to identify the head of household/key informant Qualitative Component: 1. Relatives other than parents/guardians
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The incidence rate of culture-positive typhoid fever in the late-vaccinated cohorts and the early-vaccinated cohort, measured using the number of blood culture confirmed cases during the 2 years of follow-up | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Immunity to Vi-TCV measured using anti-Vi IgG and anti-Vi IgA antibody levels in blood samples collected during 2 years of follow up 2. Immunogenicity of Vi-TCV followed by Vi-CRM197 vs Vi-CRM197 alone, measured using anti-Vi IgG and anti-Vi IgA antibody levels in blood samples collected from participants who have received both Vi-TCV and Vi-CRM197 with participants who have received Vi-CRM197 alone at one timepoint 3. Immunogenicity of Vi-CRM197 compared to Vi-TCV, measured using anti-Vi IgG and anti-Vi IgA levels in participants who have received one dose of Vi-CRM197 and participants who have received Vi-CRM197 following Vi-TCV with participants previously enrolled in immunogenicity and have received one dose of Vi-TCV at one timepoint 4. Incidence rate of culture-confirmed typhoid fever from passive surveillance in all residents, measured using the number of blood culture confirmed cases during the 2 years of follow-up 5. Sero-incidence of typhoid infection and sero-efficacy of Vi-TCV, measured using typhoid toxin (CdtB) antibody levels in blood samples collected during 2 years of follow up 6. The comparison of WASH indicators between surveys done during the TyVAC and TyVOID study at the end of TyVAC and TyVOID 7. Incidence rates of blood culture-confirmed paratyphoid from passive surveillance in all residents, measured using the number of blood culture confirmed cases during the 2 years of follow-up 8. Number of clinical diagnoses of typhoid fever, as determined by trial staff in Patan Hospital outpatient clinics and trial clinic using local clinical definitions during the 2 years of follow-up 9. Rates of hospital or clinic presentation with culture-confirmed typhoid fever illness of any duration, measured by hospital presentation logs, hospital records, trial clinic records and self-reporting during three monthly follow-ups | — |
Countries
Nepal
Outcome results
None listed