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

3. august 2026 opdateret af: 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.

Studieoversigt

Status

Rekruttering

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

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.

Undersøgelsestype

Observationel

Tilmelding (Anslået)

20000

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiesteder

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

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

  • Barn

Tager imod sunde frivillige

Ingen

Prøveudtagningsmetode

Ikke-sandsynlighedsprøve

Studiebefolkning

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.

Beskrivelse

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.

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

Kohorter og interventioner

Gruppe / kohorte
Intervention / Behandling
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
Biologisk: 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
Biologisk: 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.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Dose-specific effectiveness of R21/Matrix-M against microscopy-confirmed clinical malaria
Tidsramme: 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

Sekundære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Effectiveness of R21/Matrix-M by time since vaccination
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

Clinton Health Access Initiative Inc.

Samarbejdspartnere

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

Efterforskere

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

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Faktiske)

14. juli 2026

Primær færdiggørelse (Anslået)

1. juni 2027

Studieafslutning (Anslået)

1. august 2027

Datoer for studieregistrering

Først indsendt

3. august 2026

Først indsendt, der opfyldte QC-kriterier

3. august 2026

Først opslået (Faktiske)

6. august 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

6. august 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

3. august 2026

Sidst verificeret

1. august 2026

Mere information

Begreber relateret til denne undersøgelse

Nøgleord

Yderligere relevante MeSH-vilkår

Andre undersøgelses-id-numre

  • AVERT-2026-01
  • INV-097482 (Andet bevillings-/finansieringsnummer: Gates Foundation)
  • 2026-06-05 (Andet bevillings-/finansieringsnummer: Givewell)

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