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Assessing Vaccine Effectiveness of R21/Matrix-M Across Malaria Transmission Settings (AVERT) (AVERT)

3 de agosto de 2026 actualizado por: Clinton Health Access Initiative Inc.

Real-World Effectiveness of the R21/Matrix-M Malaria Vaccine in Children in Burkina Faso and Uganda

The AVERT study is a prospective observational test-negative case control study evaluating the real-world effectiveness of the R21/Matrix-M malaria vaccine among children younger than 5 years in Burkina Faso and Uganda. Children who seek outpatient care with suspected malaria and are eligible for the national R21/Matrix-M vaccination program will be enrolled. Malaria infection will be determined by blood smear microscopy. Children with a positive microscopy result will be classified as cases and children with a negative result as controls. Vaccination history, including the number and timing of doses, will be obtained primarily from vaccination cards or other written records. Vaccine effectiveness will be estimated by comparing the odds of vaccination among cases and controls.

Descripción general del estudio

Estado

Reclutamiento

Condiciones

Intervención / Tratamiento

Descripción detallada

R21/Matrix-M has been introduced through national immunization programs, but its effectiveness under routine conditions may differ from efficacy observed in clinical trials because children may receive different numbers of doses, doses may be delayed, protection may wane, and malaria transmission and other prevention measures vary across settings.

AVERT will use a prospective test-negative case-control design at approximately 22 outpatient health facilities in moderate- to high-transmission areas of Burkina Faso and Uganda. Consecutive children younger than 5 years who meet country definitions for suspected malaria, are eligible for R21/Matrix-M vaccination, and have caregiver consent will be enrolled. All participants will undergo malaria testing as part of routine care, with study blood smear microscopy used to assign case or control status. A structured caregiver questionnaire will collect demographic, clinical, residential, socioeconomic, health-care access, and malaria-prevention information. R21/Matrix-M dose number and vaccination dates will be verified primarily from vaccination cards, individual health records, or facility vaccination registers.

Cases and controls will be matched, when feasible, by geographic area and calendar time. Conditional or standard logistic regression will estimate adjusted odds ratios comparing vaccinated and unvaccinated children, and vaccine effectiveness will be calculated as (1 - adjusted odds ratio) x 100%. Analyses will be conducted separately by country and will assess effectiveness by dose, time since vaccination, dose spacing, transmission intensity, sex, and use of seasonal malaria chemoprevention, insecticide-treated nets, and indoor residual spraying. A health-system-perspective economic evaluation will estimate incremental cost per uncomplicated clinical malaria case averted.

Tipo de estudio

De observación

Inscripción (Estimado)

20000

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Ubicaciones de estudio

  • Burkina Faso
    • Boucle Mouhoun
      • Boromo, Boucle Mouhoun, Burkina Faso
        • Reclutamiento
        • Boromo urbain 1
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Boromo, Boucle Mouhoun, Burkina Faso
        • Reclutamiento
        • Ouahabou
        • Contacto:
          • h Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
    • Hauts-Bassins Region
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Béréba
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Dohoun
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Kari
        • Contacto:
          • Halidou Tinto
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Déguélin
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Karangasso-Vigué
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Sourmousso
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Reclutamiento
        • Wara
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
    • Oubri
      • Zorgo, Oubri, Burkina Faso
        • Reclutamiento
        • Mankarga T
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Zorgo, Oubri, Burkina Faso
        • Reclutamiento
        • Mankarga V3
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
      • Zorgo, Oubri, Burkina Faso
        • Reclutamiento
        • Mankarga V6
        • Contacto:
          • Halidou Tinto, PhD
          • Número de teléfono: +226 25 40 92 12
          • Correo electrónico: tintoh@crun.bf
  • Uganda
    • Acholi
      • Kitgum, Acholi, Uganda
        • Aún no reclutando
        • Kitgum-Matidi HCIII
        • Contacto:
      • Kitgum, Acholi, Uganda
        • Aún no reclutando
        • Namokora HCIV
        • Contacto:
      • Omoro, Acholi, Uganda
        • Aún no reclutando
        • Lalogi HCIV
        • Contacto:
    • Bunyoro
      • Kikube, Bunyoro, Uganda
        • Aún no reclutando
        • Rwenyawawa HCIII
        • Contacto:
    • Busoga
      • Kaliro, Busoga, Uganda
        • Aún no reclutando
        • Nawaikoke HCIII
        • Contacto:
      • Mayuge, Busoga, Uganda
        • Aún no reclutando
        • Kigandalo HCIV
        • Contacto:
    • Karamoja
      • Moroto, Karamoja, Uganda
        • Aún no reclutando
        • Nadunget HCIII
        • Contacto:
    • Lango
      • Otuke, Lango, Uganda
        • Aún no reclutando
        • Orum HCIV
        • Contacto:
      • Oyam, Lango, Uganda
        • Aún no reclutando
        • Otwal HCIII
        • Contacto:

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Niño

Acepta Voluntarios Saludables

No

Método de muestreo

Muestra no probabilística

Población de estudio

Children younger than 5 years who reside in the catchment areas of selected health facilities in R21/Matrix-M implementation districts in Burkina Faso or Uganda, are age-eligible for vaccination under the relevant national schedule, and present for outpatient care with suspected malaria. Participants are recruited from health facilities in moderate- to high-transmission settings.

Descripción

Inclusion Criteria:

  • Residence in an area where R21/Matrix-M is implemented and within the catchment area of a selected study facility.
  • Younger than 5 years and eligibleto receive R21/Matrix-M under the national vaccination schedule at rollout.
  • Meets the country definition of suspected malaria, generally axillary temperature of at least 37.5 degrees Celsius or a history of fever within the previous 24 hours, and is undergoing malaria testing.
  • Written informed consent provided by an adult caregiver aged 18 years or older.

Exclusion Criteria:

  • Caregiver is unable or unwilling to provide informed consent.
  • Severe non-malaria illness at presentation that would interfere with study participation.
  • Repeat presentation within the protocol-defined exclusion window after a previous enrollment: within 14 days after a microscopy-positive visit; or more than 7 but fewer than 14 days after a microscopy-negative visit. A microscopy-negative visit followed by a positive diagnosis within 7 days will be reclassified as positive rather than treated as a new enrollment.
  • Documented receipt of any RTS,S malaria vaccine dose.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

Cohortes e Intervenciones

Grupo / Cohorte
Intervención / Tratamiento
Suspected malaria cases that test positive using microscopy
Eligible children with suspected malaria whose enrollment blood smear microscopy result is positive for P. falciparum infection
Biológico: R21/Matris-M Malaria vaccine
R21/Matrix-M vaccination received through routine national immunization programs. The study will record the number and dates of doses received. Children will be classified as having received 0, 1, 2, 3, or 4 eligible doses, with prespecified grouped classifications used if individual dose categories are underpowered. Doses given fewer than 14 days before malaria testing will not count toward the primary exposure classification.
Suspected malaria cases that test negative using microscopy
Eligible children with suspected malaria whose enrollment blood smear microscopy result is negative for P. falciparum infection
Biológico: R21/Matris-M Malaria vaccine
R21/Matrix-M vaccination received through routine national immunization programs. The study will record the number and dates of doses received. Children will be classified as having received 0, 1, 2, 3, or 4 eligible doses, with prespecified grouped classifications used if individual dose categories are underpowered. Doses given fewer than 14 days before malaria testing will not count toward the primary exposure classification.

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Dose-specific effectiveness of R21/Matrix-M against microscopy-confirmed clinical malaria
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month study recruitment period
Adjusted vaccine effectiveness will be calculated as (1 - adjusted odds ratio) x 100%. The odds ratio will compare the odds of each documented R21/Matrix-M dose category among microscopy-positive malaria cases with the odds among microscopy-negative controls, using children with 0 doses as the primary reference group. Prespecified grouped dose categories will be used if individual dose categories do not have adequate statistical power.
At the enrollment illness episode, during the approximately 7- to 8-month study recruitment period

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Effectiveness of R21/Matrix-M by time since vaccination
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Adjusted vaccine effectiveness will be estimated by categorical and/or continuous time since the most recent eligible vaccine dose, including interactions between dose and time.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Effect modification of vaccine effectiveness by malaria transmission intensity
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Dose-specific vaccine effectiveness will be compared across prespecified malaria transmission levels within each country.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Effect modification of vaccine effectiveness by sex
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Dose-specific vaccine effectiveness will be estimated using vaccination-by-sex interaction terms and sex-stratified analyses.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Effect modification by other malaria prevention interventions
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Dose-specific vaccine effectiveness will be assessed in relation to seasonal malaria chemoprevention, insecticide-treated net use, and indoor residual spraying using interaction analyses.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Effectiveness according to vaccine dose timing
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Among vaccinated children, effectiveness will be compared for on-time and late vaccination and in analyses restricted to doses spaced 3 to 5 weeks apart. A late dose is defined as a dose received at least 2 weeks after the scheduled date.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Effectiveness of the fourth dose relative to the three-dose primary series
Periodo de tiempo: At the enrollment illness episode, during the approximately 7- to 8-month recruitment period
Adjusted vaccine effectiveness of 4 doses compared with 3 doses will be estimated using the odds of microscopy-confirmed malaria.
At the enrollment illness episode, during the approximately 7- to 8-month recruitment period

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Clinton Health Access Initiative Inc.

Colaboradores

University of California, San Francisco
Institut de Recherche en Sciences de la Sante, Burkina Faso
Ministry of Health, Uganda
Ministry of Health, Burkina Faso
Infectious Diseases Research Collaboration, Uganda

Investigadores

  • Investigador principal: Isabel Rodriguez-Barraquer, MD, PhD, University of California, San Francisco
  • Investigador principal: Halidou Tinto, PhD, Institut de Recherche en Sciences de la Santé (Burkina Faso)
  • Investigador principal: Joaniter Nankabirwa, MD, PhD, Infectious Diseases Research Collaboration, Kampala, Uganda

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Actual)

14 de julio de 2026

Finalización primaria (Estimado)

1 de junio de 2027

Finalización del estudio (Estimado)

1 de agosto de 2027

Fechas de registro del estudio

Enviado por primera vez

3 de agosto de 2026

Primero enviado que cumplió con los criterios de control de calidad

3 de agosto de 2026

Publicado por primera vez (Actual)

6 de agosto de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

6 de agosto de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

3 de agosto de 2026

Última verificación

1 de agosto de 2026

Más información

Términos relacionados con este estudio

Palabras clave

Términos MeSH relevantes adicionales

Otros números de identificación del estudio

  • AVERT-2026-01
  • INV-097482 (Otro número de subvención/financiamiento: Gates Foundation)
  • 2026-06-05 (Otro número de subvención/financiamiento: Givewell)

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

INDECISO

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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