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

3 augustus 2026 bijgewerkt door: 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.

Studie Overzicht

Toestand

Werving

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

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.

Studietype

Observationeel

Inschrijving (Geschat)

20000

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studie Locaties

  • Burkina Faso
    • Boucle Mouhoun
      • Boromo, Boucle Mouhoun, Burkina Faso
        • Werving
        • Boromo urbain 1
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Boromo, Boucle Mouhoun, Burkina Faso
        • Werving
        • Ouahabou
        • Contact:
          • h Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
    • Hauts-Bassins Region
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Béréba
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Dohoun
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Houndé, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Kari
        • Contact:
          • Halidou Tinto
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Déguélin
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Karangasso-Vigué
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Sourmousso
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Karangasso-Vigué, Hauts-Bassins Region, Burkina Faso
        • Werving
        • Wara
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
    • Oubri
      • Zorgo, Oubri, Burkina Faso
        • Werving
        • Mankarga T
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Zorgo, Oubri, Burkina Faso
        • Werving
        • Mankarga V3
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
      • Zorgo, Oubri, Burkina Faso
        • Werving
        • Mankarga V6
        • Contact:
          • Halidou Tinto, PhD
          • Telefoonnummer: +226 25 40 92 12
          • E-mail: tintoh@crun.bf
  • Oeganda
    • Acholi
      • Kitgum, Acholi, Oeganda
        • Nog niet aan het werven
        • Kitgum-Matidi HCIII
        • Contact:
      • Kitgum, Acholi, Oeganda
        • Nog niet aan het werven
        • Namokora HCIV
        • Contact:
      • Omoro, Acholi, Oeganda
        • Nog niet aan het werven
        • Lalogi HCIV
        • Contact:
    • Bunyoro
      • Kikube, Bunyoro, Oeganda
        • Nog niet aan het werven
        • Rwenyawawa HCIII
        • Contact:
    • Busoga
      • Kaliro, Busoga, Oeganda
        • Nog niet aan het werven
        • Nawaikoke HCIII
        • Contact:
      • Mayuge, Busoga, Oeganda
        • Nog niet aan het werven
        • Kigandalo HCIV
        • Contact:
    • Karamoja
      • Moroto, Karamoja, Oeganda
        • Nog niet aan het werven
        • Nadunget HCIII
        • Contact:
    • Lango
      • Otuke, Lango, Oeganda
        • Nog niet aan het werven
        • Orum HCIV
        • Contact:
      • Oyam, Lango, Oeganda
        • Nog niet aan het werven
        • Otwal HCIII
        • Contact:

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

  • Kind

Accepteert gezonde vrijwilligers

Nee

Bemonsteringsmethode

Niet-waarschijnlijkheidssteekproef

Studie Bevolking

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.

Beschrijving

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.

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

Cohorten en interventies

Groep / Cohort
Interventie / Behandeling
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
Biologisch: 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
Biologisch: 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.

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Dose-specific effectiveness of R21/Matrix-M against microscopy-confirmed clinical malaria
Tijdsspanne: 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

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Effectiveness of R21/Matrix-M by time since vaccination
Tijdsspanne: 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
Tijdsspanne: 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
Tijdsspanne: 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
Tijdsspanne: 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
Tijdsspanne: 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
Tijdsspanne: 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

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

Clinton Health Access Initiative Inc.

Medewerkers

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

Onderzoekers

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

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Werkelijk)

14 juli 2026

Primaire voltooiing (Geschat)

1 juni 2027

Studie voltooiing (Geschat)

1 augustus 2027

Studieregistratiedata

Eerst ingediend

3 augustus 2026

Eerst ingediend dat voldeed aan de QC-criteria

3 augustus 2026

Eerst geplaatst (Werkelijk)

6 augustus 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

6 augustus 2026

Laatste update ingediend die voldeed aan QC-criteria

3 augustus 2026

Laatst geverifieerd

1 augustus 2026

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Aanvullende relevante MeSH-voorwaarden

Andere studie-ID-nummers

  • AVERT-2026-01
  • INV-097482 (Ander subsidie-/financieringsnummer: Gates Foundation)
  • 2026-06-05 (Ander subsidie-/financieringsnummer: Givewell)

Plan Individuele Deelnemersgegevens (IPD)

Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?

ONBESLIST

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .

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