Typhoid Conjugate Vaccine Introduction in Madagascar (TyMA): Evaluation of the Real-World Effectiveness of the Vi-CRM197 Typhoid Conjugate Vaccine in Madagascar (TyMA)
This study evaluates the real-world effectiveness, safety, and immunogenicity of a single dose of the Vi-CRM197 typhoid conjugate vaccine (TCV) delivered through a mass vaccination campaign in selected districts of Madagascar. The study targets individuals aged 9 months to 45 years living in defined catchment areas with a high burden of typhoid fever.
The project integrates three components: a population census with geographic mapping, a vaccination campaign using a WHO-prequalified Vi-CRM197 TCV, and prospective surveillance for typhoid fever. Vaccine effectiveness will be assessed by comparing the incidence of blood culture-confirmed Salmonella Typhi infection among vaccinated and unvaccinated individuals during follow-up. Additional outcomes include clinically suspected typhoid fever, severe disease, vaccine safety, immunogenicity, antibiotic use and consumption, and carriage of antimicrobial resistance (AMR) markers.
The study aims to generate real-world evidence to inform public health decision-making regarding typhoid vaccine introduction and its broader impact on disease burden and antimicrobial resistance in endemic settings.
연구 개요
상세 설명
Typhoid fever, caused by Salmonella enterica serovar Typhi, remains a major public health problem in many low- and middle-income countries, particularly in settings with limited access to safe water and sanitation. The emergence of antimicrobial resistance further complicates treatment and underscores the importance of preventive strategies such as vaccination. Typhoid conjugate vaccines (TCVs) have demonstrated efficacy in clinical trials, but data on their real-world effectiveness and broader population impact in African settings remain limited.
The TyMA study evaluates the impact of a mass vaccination campaign using a WHO-prequalified Vi-CRM197 TCV in selected districts of Madagascar. The study employs a population-based design integrating a baseline census, vaccination activities, and longitudinal surveillance.
Eligible individuals aged 9 months to 45 years will receive a single intramuscular dose of Vi-CRM197 during a community vaccination campaign.
Vaccine effectiveness will be assessed through both active and enhanced facility-based surveillance for typhoid fever over approximately three years Blood culture testing will be performed for suspected cases to identify laboratory-confirmed S. Typhi infection. Effectiveness estimates will be derived by comparing incidence rates between vaccinated individuals and unvaccinated controls within the censused population.
Subgroups of participants will be enrolled in additional cohorts to evaluate specific outcomes:
- Safety cohort: Active monitoring for adverse events following vaccination
- Immunogenicity cohort: Measurement of anti-Vi IgG antibody responses over time
- Active follow-up subpopulation: Regular household visits to identify febrile illness and healthcare utilization
- AMR cohort: Assessment of antimicrobial use, consumption, and carriage of antimicrobial resistance markers
Passive surveillance in selected healthcare facilities will complement active follow-up to capture cases presenting for care. Data on antibiotic prescribing, hospitalization, and clinical outcomes will also be collected.
The study will assess direct, indirect, and overall vaccine protection at the population level and explore the impact of vaccination on antimicrobial use and resistance patterns. Findings are expected to provide critical evidence to support national and regional policy decisions regarding typhoid vaccine introduction and strategies to mitigate antimicrobial resistance.
연구 유형
등록 (추정된)
단계
- 4단계
연락처 및 위치
연구 연락처
- 이름: Florian Marks
- 전화번호: +82 10-8703-3813
- 이메일: fmarks@ivi.int
연구 장소
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Antananarivo, 마다가스카르
- 모병
- MIVR
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연락하다:
- Raphael Rakotozandrindrainy
- 전화번호: +261 32 50 267 21
- 이메일: rakrapha13@gmail.com
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참여기준
자격 기준
공부할 수 있는 나이
건강한 자원 봉사자를 받아들입니다
연구 대상 성별
설명
Inclusion Criteria:
- Age 9 months to 45 years at the time of vaccination
- Resident of the defined study catchment area in Madagascar
- Parent(s), legal guardian, or participant (if adult) able and willing to provide written informed consent (and assent where applicable)
- Willing to comply with study procedures and follow-up for the duration of the study
Exclusion Criteria:
- Any medical or social condition that, in the opinion of the investigator, would interfere with participation or study procedures
- Known allergy or hypersensitivity to any component of the Vi-CRM197 typhoid conjugate vaccine
- Parent(s), legal guardian, or participant unwilling or unable to provide informed consent/assent
공부 계획
연구는 어떻게 설계됩니까?
디자인 세부사항
- 주 목적: 방지
- 할당: 해당 없음
- 중재 모델: 단일 그룹 할당
- 마스킹: 없음(오픈 라벨)
무기와 개입
참가자 그룹 / 팔 |
개입 / 치료 |
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실험적: Vaccination Campaign: Vi-CRM197 Typhoid Conjugate Vaccine
Participants aged 9 months to 45 years residing in the defined catchment area will be offered a single intramuscular dose of the Vi-CRM197 typhoid conjugate vaccine as part of a population-based vaccination campaign. Vaccine effectiveness will be evaluated prospectively through active and facility-based surveillance for typhoid fever. |
Single-dose Vi-CRM197 typhoid conjugate vaccine administered intramuscularly to age-eligible individuals during a mass vaccination campaign. The vaccine is WHO-prequalified and intended to prevent infection with Salmonella enterica serovar Typhi. |
연구는 무엇을 측정합니까?
주요 결과 측정
결과 측정 |
측정값 설명 |
기간 |
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Incidence of blood culture-confirmed typhoid fever (Salmonella Typhi)
기간: From census enrollment up to 52 months
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Incidence of typhoid fever defined as isolation of Salmonella enterica serovar Typhi from blood culture among individuals residing in the study catchment area. Vaccine effectiveness will be estimated by comparing incidence between individuals who received a single dose of Vi-CRM197 typhoid conjugate vaccine during the vaccination campaign and unvaccinated individuals within the censused population using active and enhanced facility-based surveillance. |
From census enrollment up to 52 months
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2차 결과 측정
결과 측정 |
측정값 설명 |
기간 |
|---|---|---|
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Incidence of clinically suspected typhoid fever
기간: From census enrollment up to 52 months
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Incidence of clinically suspected typhoid fever among residents of the study catchment area identified through active household surveillance and enhanced facility-based surveillance, regardless of laboratory confirmation. Comparisons will be made between vaccinated and unvaccinated individuals. |
From census enrollment up to 52 months
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Incidence of severe typhoid fever
기간: From census enrollment up to 52 months
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Incidence of severe typhoid fever, including cases requiring hospitalization or presenting with severe complications, among vaccinated and unvaccinated individuals in the study population |
From census enrollment up to 52 months
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Solicited and unsolicited adverse events following vaccination
기간: Solicited adverse events: Days 0-7 post-vaccination of a subset of participants; Unsolicited adverse evetns : up to 28 days pos vaccination. Aerious adverse events: From vaccination enrollment up to 52 months
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Occurrence of solicited local and systemic adverse events within 7 days after vaccination and unsolicited adverse events and serious adverse events during follow-up among participants receiving the Vi-CRM197 vaccine. |
Solicited adverse events: Days 0-7 post-vaccination of a subset of participants; Unsolicited adverse evetns : up to 28 days pos vaccination. Aerious adverse events: From vaccination enrollment up to 52 months
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Anti-Vi IgG antibody response following vaccination
기간: Baseline to 24 months post-vaccination
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Immunogenicity assessed by seroconversion (≥4-fold rise in anti-Vi IgG titers from baseline) and geometric mean titers measured in a subset of vaccinated participants at predefined time points after vaccination. |
Baseline to 24 months post-vaccination
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Carriage of antimicrobial resistance markers
기간: Baseline to 12 months
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Prevalence and changes in antimicrobial resistance markers in gastrointestinal and respiratory samples among vaccinated and unvaccinated individuals in a subset cohort. |
Baseline to 12 months
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공동 작업자 및 조사자
연구 기록 날짜
연구 주요 날짜
연구 시작 (실제)
기본 완료 (추정된)
연구 완료 (추정된)
연구 등록 날짜
최초 제출
QC 기준을 충족하는 최초 제출
처음 게시됨 (실제)
연구 기록 업데이트
마지막 업데이트 게시됨 (실제)
QC 기준을 충족하는 마지막 업데이트 제출
마지막으로 확인됨
추가 정보
이 연구와 관련된 용어
키워드
추가 관련 MeSH 약관
기타 연구 ID 번호
- TyMA-WS-03-2023
약물 및 장치 정보, 연구 문서
미국 FDA 규제 의약품 연구
미국 FDA 규제 기기 제품 연구
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