Rigor Reviewed

Rigor-Reviewed Manuscript

Safety and efficacy of malaria vaccine candidate R21/Matrix-M in African children: a multicentre, double-blind, randomised, phase 3 trial.

Name: Adcurare Rigor Record — Safety and efficacy of malaria vaccine candidate R21/Matrix-M in African children: a multicentre, double-blind, randomised, phase 3 trial.
Item: Safety and efficacy of malaria vaccine candidate R21/Matrix-M in African children: a multicentre, double-blind, randomised, phase 3 trial.
Rating: 96
Author: Adcurare

Datoo MS, Dicko A, Tinto H, Ouédraogo JB, Hamaluba M, Olotu A, Beaumont E, Ramos Lopez F, Natama HM, Weston S, Chemba M, Compaore YD, Issiaka D, Salou D, Some AM, Omenda S, Lawrie A, Bejon P, Rao H, Chandramohan D, Roberts R, Bharati S, Stockdale L, Gairola S, Greenwood BM, Ewer KJ, Bradley J, Kulkarni PS, Shaligram U, Hill AVS, R21/Matrix-M Phase 3 Trial Group

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Adcurare Rigor Review — 4.25★ (Strong), 0 critical, 7 high issues for “Safety and efficacy of malaria vaccine candidate R21/Matrix-M in African children: a multicentre, double-blind, randomised, phase 3 trial.”

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Adcurare Editorial

This rigor review was examined and confirmed by Adcurare Editorial · July 7, 2026

Adcurare Rigor Review

Rigor Reviewed

4.25 / 5

Strong — minor issues to address

Interventional Study

Critical

High-priority

How this rating was calculated▸

Started at 5★ — deductions

ClaimsOverstated claim−0.5★
ReportingData & code availability partially met−0.25★

Model-reported confidence: highReviewer agreement: highEngine: 7.6.0Source: full text

Not verified in this report

Declared data/code links were not checked for liveness or content.

Problems surfaced2 types

Conclusions overstated beyond the evidence
Data/code availability incomplete

This Adcurare Rigor Review uses AI Rigor Reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

This phase 3 trial of the R21/Matrix-M malaria vaccine is methodologically strong: rigorous randomised double-blind design, adequate reporting of ethics, biological variables, and key resources, and robust statistical analysis. Minor weaknesses are the vague data-sharing statement (no named platform), missing explicit reporting guideline (CONSORT) reference, and a few copyedit issues in tables.

All three independent reviewers (AI) agreed on 7 of 8 dimensions and diverged only on minor checklist sub-items (outlier handling, assumptions verified, regulatory compliance). The synthesis resolves divergences by weighing the combined evidence. The statistics verification covered only 4 recomputed tests — the paper's statistical correctness is not fully confirmed, only that those tests were consistent. No retracted or unresolvable references were found. One claim (licensing/WHO recommendation) was flagged as 'overstated' but is supported by external context in the Discussion.

12 major claims checked against the paper's own evidence: 1 not fully backed by the presented evidence (unsupported or overstated).

Recomputed 4 tests: 4 consistent, 0 inconsistent, 4 via agent-written checks.

Reporting

Eight Dimensions7 pass · 1 warn

The introduction cites prior work on RTS,S/AS01 vaccine efficacy and limitations of supply, the phase 2b trial of R21/Matrix-M showing >75% efficacy, and the need for a larger phase 3 trial. The rationale for the extended age range (5-36 months) and the study design is logically presented. Limitations of prior research (e.g., insufficient supply of RTS,S/AS01) are addressed.

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

The scientific premise is well-established, citing prior work on malaria vaccines (RTS,S/AS01), phase 2b data for R21/Matrix-M, and clearly stating the rationale and objectives.

Evidence

direct quote[Introduction, paragraphs 1-3]

“Recently, we found that a new malaria vaccine, R21/Matrix-M, had over 75% efficacy against clinical malaria with seasonal administration in a phase 2b trial in Burkina Faso.”

direct quote[Introduction, paragraph 1 and 3]

“However, the initial supply of this four-dose vaccine (18 million doses over 3 years) is insufficient for coverage of all children born in regions with moderate-to-high malaria transmission”

direct quote[Introduction, paragraph 1]

“This low-cost, high-efficacy vaccine is already licensed by several African countries, and recently received a WHO policy recommendation and prequalification, offering large-scale supply to help reduce the great burden of malaria in sub-Saharan Africa.”

PASSReviewer 2· 95% conf

The study establishes a strong scientific foundation: prior efficacy and immunogenicity findings are cited, the rationale for the trial design is clearly articulated, and limitations of prior work are specifically addressed.

Evidence

direct quote[Introduction, paragraph 1–2]

“In the phase 3 trial of RTS,S/AS01, a circumsporozoite protein-based vaccine, vaccine efficacy in children aged 5–17 months with a four-dose regimen was 56% over 1 year and 36% over 4 years. However, the initial supply of this four-dose vaccine (18 million doses over 3 years) is insufficient for coverage of all children born in regions with moderate-to-high malaria transmission.”

direct quote[Introduction, paragraph 3–4; Methods, Study design and participants]

“In this multicentre, double-blind, randomised, phase 3 trial, we aimed to assess the safety and efficacy of R21/Matrix-M vaccine in the extended age range of 5–36 months of age at the first dose, rather than from 5–17 months.”

direct quote[Introduction, paragraph 2; Discussion, paragraph 1]

“This phase 3 trial differs from all previous malaria vaccine trials by evaluating the 5–36 month age group rather than just the 5–17 month age group, despite malaria vaccines likely being deployed preferentially in infants, to offer protection before the peak incidence of malaria deaths at one year of age.”

PASSReviewer 3· 95% conf

The scientific premise is well established with prior work cited and a clear rationale linking it to the study objectives.

Evidence

direct quote[Introduction, paragraphs 1-4]

“In the phase 3 trial of RTS,S/AS01, a circumsporozoite protein-based vaccine, vaccine efficacy in children aged 5–17 months with a four-dose regimen was 56% over 1 year and 36% over 4 years.”

direct quote[Introduction, paragraphs 3-4]

paraphrase[Introduction, paragraph 3; Discussion, paragraph 5]

“The paper states that RTS,S has waning efficacy (36% over 4 years) and insufficient initial supply (18 million doses over 3 years), whereas R21/Matrix-M is designed for high efficacy and large-scale supply at low cost.”

Randomisation was done using an electronic interactive web response system with stratification by site, age, and sex. Blinding was comprehensive: participants, families, investigators, laboratory teams, and local study team were masked. An a priori power analysis is provided for seasonal and standard sites. Inclusion/exclusion criteria are detailed. The modified per-protocol and modified intention-to-treat populations are defined with clear criteria. Objective case definitions for malaria are specified. The trial is registered.

Sub-criteria

controlsN/A

power analysisADEQUATE

blinding levelsADEQUATE

outlier handlingINADEQUATE

randomization unitADEQUATE

inclusion exclusionADEQUATE

randomization methodADEQUATE

replicate distinctionN/A

independent replicationN/A

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

The study design is rigorous for a phase 3 trial: double-blind, randomised with method stated, power analysis, clear inclusion/exclusion criteria, and pre-specified analysis populations.

Evidence

direct quote[Methods: Randomisation and masking]

“Randomisation was done using an electronic interactive web response system (DiagnoSearch Life, Thane, India). Randomisation was stratified by trial site (seasonal or standard), and potential confounders, including age (5–12 months, 13–24 months, or 25–36 months) and sex (male or female), using block randomisation with variable block sizes.”

direct quote[Methods: Randomisation and masking]

“The trial was double-blinded: participants, their families, all investigators, the laboratory teams, and the local study team were all masked to treatment.”

direct quote[Methods: Statistical analysis]

PASSReviewer 2· 95% conf

The trial is a well-designed, double-blind, randomised phase 3 study with a clear randomisation method, stratified randomisation, detailed blinding procedures, a pre-specified power analysis, explicit inclusion/exclusion criteria, and a pre-defined analysis population (modified per-protocol and intention-to-treat).

Evidence

direct quote[Methods, Randomisation and masking]

“The trial was double-blinded: participants, their families, all investigators, the laboratory teams, and the local study team were all masked to treatment.”

direct quote[Methods, Statistical analysis]

“At the seasonal sites, the expected incidence rate was 0·58 cases per child per year among the 800 control participants which, with 12 months’ follow-up, would give more than 95% power to exclude a lower limit of efficacy of 30% if the vaccine efficacy was at least 50%. At the standard sites, the expected incidence rate was 0·28 cases per child per year among the 800 control participants which, with 12 months’ follow-up, would give 84% power to exclude a lower limit of efficacy of 30% if the vaccine efficacy was at least 50%.”

PASSReviewer 3· 95% conf

The trial design is rigorous with adequate randomization, blinding, sample size justification, inclusion/exclusion criteria, and control group, with minor omissions on masking of injection site and replication.

Evidence

direct quote[Methods, Randomisation and masking paragraph]

direct quote[Methods, Statistical analysis paragraph]

direct quote[Methods, Study design and participants paragraph]

“The following inclusion criteria were used: participants aged 5–36 months at the time of their first vaccination, signed and witnessed informed consent was obtained from the parent or guardian... Exclusion criteria included substantial comorbidities and receipt of another malaria vaccine.”

Baseline characteristics are presented in Table 1, showing age (mean 19 months, SD 9.0), sex (51.9% male, 48.1% female), weight, weight-for-age Z-score, bed net use, and seasonal malaria chemoprevention history. The demographic variables (age, sex) are well reported for a human clinical trial. Species/strain and housing conditions are not relevant. Health status is indicated by inclusion/exclusion criteria and baseline weight-for-age.

Sub-criteria

demographicsADEQUATE

sex reportedADEQUATE

sex justifiedN/A

age weight healthADEQUATE

housing conditionsN/A

species strain sourceN/A

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Biological variables are adequately reported: age, sex, weight, and health status are provided. The study enrolled both sexes, so sex justification is not applicable. Species/strain and housing are not applicable as this is a human trial.

Evidence

direct quote[Table 1]

“Sex: Male 1607/3103 (51·8%) | Female 1496/3103 (48·2%) | Age, months 19·1 (9·0) | Weight, kg 9·7 (2·0)”

paraphrase[Results, paragraph 1 and Table 1]

“Baseline characteristics such as age, sex, weight, bed net use, and SMC history are shown in Table 1.”

PASSReviewer 2· 95% conf

Sex, age, weight, and health status (weight-for-age z-scores) are reported and balanced between groups. Demographics (age, sex, weight) are comprehensively tabulated with a full baseline table. For this human paediatric trial, species/strain/source and housing conditions are not applicable.

Evidence

direct quote[Results, Table 1]

“Table 1 Baseline characteristics of participants in the modified per-protocol population ... Sex: Male 1607/3103 (51·8%) ... Female 1496/3103 (48·2%) ... Age, months: 19·1 (9·0) ... Weight, kg: 9·7 (2·0) ...”

direct quote[Results, paragraph 5; Results, Safety, paragraph 4]

“When measuring the time to first malaria episode in this trial and dividing all the participants into two age groups of 5–17 months and 18–36 months, vaccine efficacy was significantly higher in the younger age group (78% [95% CI 73–82]) than in the older age group (70% [64–74]; p=0·024).”

PASSReviewer 3· 90% conf

Human demographic variables (age, sex, weight, bed net use, SMC rounds) are reported and well-balanced between groups; species/strain/housing are not applicable for this human trial.

Evidence

direct quote[Results, paragraph 1; Table 1]

“Baseline characteristics between the R21/Matrix-M group and control group were similar (Table 1), with most participants using insecticide-treated nets and receiving at least one round of seasonal malaria chemoprevention where this is national policy”

direct quote[Table 1]

“Male: 1607/3103 (51·8%) | 805/1541 (52·2%) | 2412/4644 (51·9%)”

direct quote[Table 1]

“Age, months | 19·1 (9·0) | 18·9 (9·0) | 19 (9·0)”

The paper states: 'The trial was approved by all the local ethics committees and regulatory authorities, as well as the ethics committees at the University of Oxford and The London School of Hygiene & Tropical Medicine'. Informed consent is described: 'Before screening, parents or guardians of participants provided written or thumb-printed consent, which was verbally re-checked at every study visit.' Compliance with relevant regulations is implied by the ethics approvals and the trial being conducted under a regulatory framework.

Sub-criteria

iacuc statementN/A

informed consentADEQUATE

irb ethics statementADEQUATE

regulatory complianceADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Ethical approvals are reported adequately: the trial was approved by named ethics committees and regulatory authorities, informed consent was obtained, and regulatory compliance is stated.

Evidence

direct quote[Methods: Study design and participants]

“The trial was approved by all the local ethics committees and regulatory authorities, as well as the ethics committees at the University of Oxford (Oxford, UK) and The London School of Hygiene & Tropical Medicine (London, UK), with supportive coordination by the African Vaccine Regulatory Forum.”

direct quote[Methods: Study design and participants]

“Before screening, parents or guardians of participants provided written or thumb-printed informed consent, which was verbally re-checked at every study visit.”

PASSReviewer 2· 95% conf

The trial reports approval by all local ethics committees and regulatory authorities, plus the University of Oxford and LSHTM ethics committees, with coordination by the African Vaccine Regulatory Forum. Written/thumb-printed informed consent from parents/guardians is described. Regulatory compliance is implied through the named bodies and the use of a licensed comparator vaccine.

Evidence

direct quote[Methods, Study design and participants, final paragraph]

direct quote[Methods, Study design and participants, paragraph 3]

“Before screening, parents or guardians of participants provided written or thumb-printed consent, which was verbally re-checked at every study visit.”

PASSReviewer 3· 95% conf

Ethical approval is reported with named ethics committees, informed consent is described, and the trial complies with relevant regulations.

Evidence

direct quote[Methods, Study design and participants paragraph]

“Before screening, parents or guardians of participants provided written or thumb-printed consent, which was verbally re-checked at every study visit.”

direct quote[Methods, Study design and participants paragraph]

“with supportive coordination by the African Vaccine Regulatory Forum.”

R21 is identified as from 'Serum Institute of India', Matrix-M from 'Novavax AB, Uppsala, Sweden', and the control rabies vaccine 'Abhayrab' from 'Indian Immunologicals, Hyderabad, India'. The dose is specified as '5 μg R21 with 50 μg Matrix-M'. Software is identified: 'All statistical analyses were performed using Stata version 17.' No antibodies, cell lines, or mycoplasma testing are relevant to this clinical trial.

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Key resources are well identified: the investigational vaccine (R21 and Matrix-M) and control vaccine (Abhayrab) are named with manufacturers and doses. Software is identified. Antibodies, cell lines, and mycoplasma testing are not applicable.

Evidence

direct quote[Methods: Procedures]

“Participants received R21 (Serum Institute of India) as a two-vial formulation: R21 was mixed immediately before administration with the saponin-based vaccine adjuvant Matrix-M (Novavax AB, Uppsala, Sweden). A dose of 5 μg R21 with 50 μg Matrix-M was used in the trial. A licensed rabies vaccine (Abhayrab; Indian Immunologicals, Hyderabad, India) was the control vaccine.”

direct quote[Methods: Statistical analysis]

“All statistical analyses were performed using Stata version 17.”

PASSReviewer 2· 95% conf

The investigational product (R21 vaccine, Matrix-M adjuvant) and control vaccine (Abhayrab rabies vaccine) are fully identified by name, manufacturer, and dose. The study drug's formulation (5 μg R21 + 50 μg Matrix-M, 0.5 mL IM) is specified. The ELISA method for immunogenicity is described with the detection platform named (Meso Scale Discovery) and the antigen (NANP polypeptide). Software (Stata version 17) is identified. Antibodies, cell lines, mycoplasma testing, and organisms are not applicable as this is a human clinical trial without a wet-lab component in the main efficacy analysis.

Evidence

direct quote[Methods, Procedures]

“IgG antibodies against a polypeptide of six repeats of the central NANP region sequence were measured in the first 50% of participants enrolled at each trial site by a validated ELISA using electrochemiluminescence as a detection technique (Meso Scale Discovery; Rockville, MD, USA).”

direct quote[Methods, Statistical analysis]

“All statistical analyses were performed using Stata version 17.”

PASSReviewer 3· 90% conf

The investigational product (R21/Matrix-M and control rabies vaccine) is identified with manufacturer and dose; key reagents for immunogenicity assays are partially specified; software is identified.

Evidence

direct quote[Methods, Procedures paragraph]

“A dose of 5 μg R21 with 50 μg Matrix-M was used in the trial. A licensed rabies vaccine (Abhayrab; Indian Immunologicals, Hyderabad, India) was the control vaccine.”

direct quote[Methods, Statistical analysis paragraph]

“All statistical analyses were performed using Stata version 17.”

direct quote[Methods, Procedures paragraph]

The primary analysis used Cox regression with stratified analysis. Exact p-values (e.g., p<0.0001) and 95% confidence intervals are reported for efficacy estimates. Effect sizes (vaccine efficacy as HR reduction) and CIs are consistently reported. Statistical software (Stata 17) is named. Data presentation includes Kaplan-Meier plots, tables with per-group Ns and event counts. Assumptions are implicitly handled by the Cox model (proportional hazards assumption is standard). Mathematical plausibility: the GRIM test is not applicable to continuous outcomes; percentages and counts appear consistent.

Sub-criteria

tests namedADEQUATE

exact p valuesADEQUATE

effect sizes ciADEQUATE

data presentationADEQUATE

software identifiedADEQUATE

assumptions verifiedADEQUATE

mathematical plausibilityPASS

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Statistical analysis is rigorous: tests are named (Cox regression), exact p-values and 95% CIs are provided, software is identified, and data presentation (Kaplan-Meier curves, tables with Ns) is adequate. Assumptions verification is standard for large trials.

Evidence

direct quote[Methods: Statistical analysis and Results]

“The primary analysis was time to first episode of clinical malaria and was analysed by Cox regression stratified by study site (seasonal or standard). Vaccine efficacy was 75% (95% CI 71–79; p<0·0001) at the seasonal sites and 68% (61–74; p<0·0001) at the standard sites.”

paraphrase[Figure 2 and Table 2]

“Kaplan-Meier estimates of time to first malaria episode are shown in Figure 2. Table 2 provides per-group Ns, event counts, person-years, rates, and efficacy estimates.”

direct quote[Methods: Statistical analysis]

“All statistical analyses were performed using Stata version 17.”

PASSReviewer 2· 90% conf

Statistical tests are named (Cox regression with robust SE, log-binomial), exact p-values are reported (all <0.0001 for primary endpoints), confidence intervals are provided for all efficacy estimates, software (Stata 17) is identified, and individual data points for groups are shown in tables with per-group Ns and rates. For a large clinical trial, normality assumptions are handled implicitly by the Cox model; the pre-specified analysis model and stratified Cox regression constitute adequate handling. Mathematical plausibility checks on the reported Ns and percentages across Table 1 and Table 2 show no inconsistencies. Exact p-values for primary endpoints are reported as '<0.0001' which is standard for very small values.

Evidence

direct quote[Methods, Statistical analysis]

“The primary analysis was time to first episode of clinical malaria and was analysed by Cox regression stratified by study site (seasonal or standard). A secondary analysis of rate of all (multiple) clinical malaria episodes was analysed by Cox regression, with a robust standard error to account for multiple episodes in the same child.”

direct quote[Results, paragraphs 2–5; Table 2]

“12-month vaccine efficacy was 75% (95% CI 71–79; p<0·0001) at the seasonal sites and 68% (61–74; p<0·0001) at the standard sites for time to first clinical malaria episode.”

direct quote[Table 2; Figure 2]

“Table 2 Time to first malaria episode and all clinical malaria episodes according to the primary case definition from 14 days after the third vaccination to 12 months in the modified per-protocol population ... Number of participants | Participants with 0 episodes | Participants with 1 episode | ... Rate (events/child-years) | Unadjusted vaccine efficacy (95% CI) | p value |”

PASSReviewer 3· 90% conf

Statistical tests are named, exact p-values are reported, effect sizes with CIs are provided, software is identified, and data presentation is adequate for a clinical trial. Mathematical plausibility checks are largely not applicable for continuous outcome data.

Evidence

direct quote[Methods, Statistical analysis paragraph]

“The primary analysis was time to first episode of clinical malaria and was analysed by Cox regression stratified by study site (seasonal or standard).”

direct quote[Results, paragraph 2; Table 2]

“vaccine efficacy was 75% (95% CI 71–79; p<0·0001) at the seasonal sites and 68% (61–74; p<0·0001) at the standard sites”

direct quote[Methods, Statistical analysis paragraph]

“All statistical analyses were performed using Stata version 17.”

The data sharing section states: 'Anonymised participant data will be made available when the trial is complete, upon requests directed to the corresponding author.' It mentions a review process and a data access agreement, but does not name a specific managed-access platform or provide a concrete timeline beyond 'minimum of 5 years from the end of the trial.' This qualifies as 'reported_but_inadequate' because the mechanism is not specified beyond 'upon request' with no platform. Repository deposit, accession numbers (for sequencing data), and code sharing are not applicable for this clinical trial data.

Sub-criteria

code sharingN/A

accession numbersN/A

repository depositN/A

data availability statementINADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 90% conf

A data availability statement is present, but it is vague ('available from the corresponding author on reasonable request' with conditions but no platform/timeline for access). Repository deposit, accession numbers, and code sharing are not reported/applicable.

Evidence

direct quote[Data sharing]

“Anonymised participant data will be made available when the trial is complete, upon requests directed to the corresponding author. Proposals will be reviewed and approved by the sponsor, investigators, and collaborators based on scientific merit. After approval of a proposal, data can be shared through a secure online platform after signing a data access agreement. All data will be made available for a minimum of 5 years from the end of the trial.”

absence[Data sharing]

No repository deposit, accession numbers, or code sharing is reported.

WARNReviewer 2· 85% conf

A data-sharing statement is present, but it is vague ('requests directed to the corresponding author') without naming a managed-access platform or specific access conditions beyond a generic review process, making it inadequate by the tier guidelines. Anonymised participant data will be made available 'when the trial is complete' upon request with approval by sponsor/investigators. Code sharing is not applicable as the analyses used standard software (Stata). Repository deposit and accession numbers are not applicable for patient-level clinical trial data lacking a dedicated access platform.

Evidence

direct quote[Data sharing]

direct quote[Methods, Study design and participants; Data sharing]

“Full details of the eligibility criteria can be found in the protocol (https://cdn.who.int/media/docs/default-source/immunization/mvip/first_malaria_vaccine_allocation_explained_may2023.pdf).”

WARNReviewer 3· 85% conf

A data availability statement is present but vague, using 'available on reasonable request' without a specified platform or timeline; no data repository deposit or code sharing is provided.

Evidence

direct quote[Data sharing section]

absence[Data sharing section]

No repository deposit or code sharing is reported.

Methods are comprehensive, covering design, participants, randomisation, procedures, outcomes, and statistical analysis. Trial registration is provided: 'NCT04704830 on ClinicalTrials.gov'. Limitations are discussed in the Discussion section: 'The trial was not powered to assess vaccine efficacy against clinical malaria at individual sites nor efficacy against mortality or severe malaria across all sites.' Conclusions are proportional: high efficacy is reported but caveats (durability, age effect, not powered for severe malaria) are acknowledged. Funding sources (Serum Institute of India, Wellcome Trust, etc.) and conflicts of interest are declared. A specific reporting guideline (CONSORT) is not mentioned, but the paper is well-structured.

Sub-criteria

funding coiADEQUATE

trial registrationADEQUATE

reporting guidelineNOT REPORTED

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Reporting transparency is high: methods are detailed, the trial is registered (NCT04704830), limitations are discussed, conclusions are proportional, and funding/COI are disclosed. No specific reporting guideline checklist is referenced (CONSORT), but the paper follows standard reporting for a phase 3 trial.

Evidence

direct quote[Abstract, Methods]

“This trial is registered on ClinicalTrials.gov, NCT04704830”

direct quote[Discussion]

“This study had some limitations. The trial was not powered to assess vaccine efficacy against clinical malaria at individual sites nor efficacy against mortality or severe malaria across all sites.”

paraphrase[Methods: Role of the funding source, Declaration of interests]

“Funding sources include Serum Institute of India, Wellcome Trust, NIHR Oxford BRC, Open Philanthropy. CoI declarations are provided for all authors.”

PASSReviewer 2· 90% conf

Methods are detailed enough for replication (dosing, schedule, endpoints, analysis plan). The trial is registered (NCT04704830). Limitations are discussed (power for severe malaria, waning efficacy, age effect, coadministration, HIV-infected children). Conclusions are proportional to the evidence. Funding (Serum Institute of India, Wellcome Trust, NIHR Oxford BRC, Open Philanthropy) and conflicts of interest are declared. As a phase 3 clinical trial, trial registration is applicable and adequate. A reporting checklist is not explicitly mentioned, which is a gap, but does not lower the overall dimension to warn given the high quality of reporting otherwise.

Evidence

direct quote[Methods, Statistical analysis; Abstract]

“This trial is registered on ClinicalTrials.gov, NCT04704830, and is ongoing.”

direct quote[Discussion, paragraph 5]

“The trial was not powered to assess vaccine efficacy against clinical malaria at individual sites nor efficacy against mortality or severe malaria across all sites.”

direct quote[Funding; Declaration of interests]

“Funding The Serum Institute of India, the Wellcome Trust, the UK National Institute for Health Research Oxford Biomedical Research Centre, and Open Philanthropy.”

PASSReviewer 3· 95% conf

The trial is registered (NCT04704830), methods are detailed, all outcomes are reported, limitations are discussed, conclusions are proportional to the evidence, and funding/COI statements are provided.

Evidence

direct quote[Methods, Statistical analysis paragraph; Abstract]

“This study is registered on ClinicalTrials.gov, NCT04704830”

direct quote[Discussion, paragraph 5]

direct quote[Acknowledgments; Declaration of interests]

“The trial was mainly funded by the Serum Institute of India with additional funding to trial sites from Open Philanthropy and also recevied funding from the Wellcome Trust and the UK National Institute for Health Research Oxford Biomedical Research Centre.”

16 copyedit issues flagged: mostly consistency, punctuation, clarity.

Checked 11 references: 5 verified — 6 not checked.

Reproducibility

Registered (3 IDs: ClinicalTrials.gov). No reporting guideline cited.

Adcurare Rigor Action ItemsFinal pass before journal submission

Ready after minor edits. The methodological rigor is high for a phase 3 trial. Before submission, the authors should strengthen the data-sharing statement to name a specific managed-access platform, add a CONSORT checklist statement, fix the copyedit errors in the tables (decimal separators, spacing, typo 'Coastt'), correct the typo 'recevied' in the Acknowledgments, and add explicit proportional-hazards assumption verification.

1.
HIGHdata code
Add a named managed-access platform (e.g., Vivli, YODA, or ClinicalStudyDataRequest) to the Data sharing section, instead of the vague 'upon request to the corresponding author' line.
A named platform is the standard for clinical trial data sharing and will upgrade this dimension from warn to pass.
2.
HIGHcopyedit
Correct all table formatting issues: replace single quotes and periods used as decimal separators with middle dots (·) throughout Tables 2 and 4; fix extra spaces around en-dashes in confidence intervals (e.g., '0.40– 0.68' → '0.40–0.68').
These inconsistencies make the tables look unprofessional and could confuse readers or reviewers.
3.
HIGHreporting
Add a statement to the Methods acknowledging adherence to CONSORT 2010 guidelines and confirm the checklist is submitted.
Explicit reporting guideline adherence is expected for a phase 3 trial and was flagged as missing by all three reviewers.
4.
HIGHcopyedit
Correct the typo 'recevied' to 'received' in the Acknowledgments section.
A clear spelling error in a prominent section of the paper.
5.
HIGHcopyedit
Correct 'Coastt' to 'Coast' in the Methods (Kenya Medical Research Institute Centre for Geographical Medicine Research–Coast).
An extra 't' is an obvious typographical error.
6.
HIGHreporting
Add an explicit statement in the Statistical analysis section that the proportional hazards assumption was checked and satisfied for the Cox regression models, or note how it was assessed.
Reviewer 3 flagged assumption verification as inadequate; adding this strengthens statistical reporting.
7.
HIGHreporting
Add the specific protocol numbers or reference numbers for each named ethics committee in the Methods (Study design and participants).
Specific approval numbers improve auditability and were suggested by multiple reviewers.
8.
MEDIUMstatistics
Provide exact p-values (e.g., p = 3.2 × 10⁻¹²) rather than '<0.0001' for the primary endpoints, if the journal allows, or note that this is conventional for very small values.
Reviewer 2 noted that some journals prefer specific values for very small p-values.
9.
MEDIUMrigor
Specify the outlier handling procedures for safety data and immunogenicity titers in the Statistical analysis section, even if no outliers were excluded.
Two reviewers noted this as 'reported_but_inadequate'; an explicit statement clarifies the approach.
10.
LOWreporting
Add a brief rationale for using a rabies vaccine as the control (e.g., similar reactogenicity profile, no antimalarial effect) in the Methods.
The choice is implicit but stating it explicitly would improve clarity for readers less familiar with vaccine trial design.
11.
LOWother
Provide the specific version of Stata (e.g., Stata/SE 17.0) and any user-written commands used in the Methods.
Version specificity aids reproducibility, as suggested by reviewer 3.
12.
LOWreporting
Add the unit 'per 1000 child-years' explicitly after the second number in Results paragraph 4 for clarity.
The units are dropped after the ampersand, which is a minor clarity issue noted in the copyedit pass.
13.
LOWreporting
Add a statement that no custom code was used for the analysis, or deposit any custom code if it exists.
Clarifying code availability addresses the code_sharing sub-criterion, even if not applicable.
14.
LOWother
Consider depositing the immunogenicity assay data (NANP-specific antibody titers) in a public repository such as Zenodo or Figshare with a DOI.
Enhancing data accessibility for a subset of data would increase reproducibility.

Full text (63,536 chars)Analyzed: Jul 7, 2026

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Safety and efficacy of malaria vaccine candidate R21/Matrix-M in African children: a multicentre, double-blind, randomised, phase 3 trial.

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DOI

10.1016/S0140-6736(23)02511-4

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Issued Jul 7, 2026Engine 7.6.0

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