Evidence map›Paper›PMID 41740461›Full record

ArticleVaccine2026

The safety, reactogenicity, and immunogenicity of the self-amplifying mRNA COVID-19 vaccine GRT-R910 as a booster in healthy adults.

Jennifer A Whitaker, Paulina A Rebolledo, Getahun Abate, Tara M Babu, Nadine G Rouphael, Anna Wald, Hana M El Sahly, Karin Jooss, Meghan G Hart, Mat Makowski and 15 more

Registry-linked trialAbstract readClinical Trial, Phase I
PubMed Full text at PMC Publisher
In one paragraph

Article in Vaccine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04776317 (A Phase 1 Trial to Evaluate the Safety, Immunogenicity, and Reactogenicity of Heterologous and Homologous Chimpanzee Adenovirus and Self-Amplifying mRNA Prime-Boost Prophylactic Vaccines Against SARS-CoV-2 in Healthy Adults), which is not on this map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT04776317 phase1completednot on this map

A Phase 1 Trial to Evaluate the Safety, Immunogenicity, and Reactogenicity of Heterologous and Homologous Chimpanzee Adenovirus and Self-Amplifying mRNA Prime-Boost Prophylactic Vaccines Against SARS-CoV-2 in Healthy Adults

TypeinterventionalSponsorNational Institute of Allergy and Infectious Diseases (NIAID)Ran2021 to 2023Enrolled81ConditionsCOVID-19ArmsChAdV68-S, ChAdV68-S-TCE, SAM-LNP-S, SAM-LNP-S-TCE, Sodium Chloride, 0.9%
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

25 authors.

Jennifer A WhitakerDepartments of Molecular Virology and Microbiology and Medicine, Baylor College of Medicine, Houston, TX, USA.
Paulina A RebolledoHope Clinic, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA, USA; Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Getahun AbateCenter for Vaccine Development, Division of Infectious Diseases, Allergy and Immunology, Departments of Internal Medicine, Saint Louis University, Saint Louis, MO, USA.
Tara M BabuDivision of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA.
Nadine G RouphaelHope Clinic, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA, USA.
Anna WaldDivision of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA; Department of Epidemiology, University of Washington, Seattle, WA, USA; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
Hana M El SahlyDepartments of Molecular Virology and Microbiology and Medicine, Baylor College of Medicine, Houston, TX, USA.
Karin JoossGritstone bio, Inc. Emeryville, CA, USA.
Meghan G HartGritstone bio, Inc. Emeryville, CA, USA.
Mat MakowskiThe Emmes Company, LLC, Rockville, MD, USA.
Jinjian MuThe Emmes Company, LLC, Rockville, MD, USA.
Andrea CarmackThe Emmes Company, LLC, Rockville, MD, USA.
Janet I ArcherFHI 360, Durham, NC, USA.
Paul C RobertsDivision of Microbiology and Infectious Diseases, NIAID, NIH, Rockville, MD, USA.
Mamodikoe MakheneDivision of Microbiology and Infectious Diseases, NIAID, NIH, Rockville, MD, USA.
Christine M PosavadDepartment of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
M Juliana McElrathDivision of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
Stephen C De RosaDepartment of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA; Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
Rhea ColerSeattle Children's Research Institute, Center for Global Infectious Disease Research, Seattle, WA, USA.
David MontefioriDepartment of Surgery, Duke University Medical Center, Durham, NC, USA; Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA.
Amanda EatonDepartment of Surgery, Duke University Medical Center, Durham, NC, USA; Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA.
Mehul S SutharCenter for Childhood Infections and Vaccines, Children's Healthcare of Atlanta, Division of Infectious Diseases, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30329, USA.
Robert L AtmarDepartment of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, USA.
Daniel F HoftCenter for Vaccine Development, Division of Infectious Diseases, Allergy and Immunology, Departments of Internal Medicine, Saint Louis University, Saint Louis, MO, USA; Department of Molecular Microbiology & Immunology, Saint Louis University, Saint Louis, MO, USA. Electronic address: daniel.hoft@slu.edu.
DMID 20-0034 Study Team

Funding

Leadership Group for the Infectious Diseases Clinical Research Consortium (IDCRCLG) - Momi-Vax DMID #21-0004 {Supplement #6}UM1AI148684 · NIAID · EMORY UNIVERSITY · PI DAVID S STEPHENS · 2020 to 2026
$77.2M
Vaccine and Treatment Evaluation Unit at Saint Louis University - DMID 20-0034UM1AI148685 · NIAID · SAINT LOUIS UNIVERSITY · PI Daniel F. Hoft · 2020 to 2026
$34.6M
NIAID NIH HHS UM1 AI148684NIAID NIH HHS UM1 AI148685
6 · The paper itself

Abstract

backgroundGRT-R910 (Gritstone bio, Inc), a self-amplifying mRNA vaccine expressing SARS CoV-2 (D614G) spike protein and T-cell epitopes, was evaluated as a booster vaccine in a phase 1 study in 2021-2022.

methodsThis open-label, dose escalation study enrolled healthy adults ≥112 days after completion of primary COVID-19 vaccination, booster of approved mRNA COVID-19 vaccine, or known SARS-CoV-2 infection. Persons aged 18-60 years received single doses of 3 or 6 μg GRT-R910 (n = 10/group). Persons >60 years of age received GRT-R910 at 3, 6, or 10 μg (n = 8-10/group). Safety and immunogenicity responses were assessed for 1 year after vaccination.

resultsWe enrolled 48 participants. Most participants developed mild-to-moderate systemic reactions and/or injection site tenderness. Eight of 48 (17%) had severe systemic reactions. Pseudovirus neutralizing antibody geometric mean fold rise (GMFR) responses against SARS-CoV-2 (D614G) at Day 29 and Day 181, respectively, among those ≤60 years were 5.2 (95% CI 2.1, 13.3) and 6.1 (2.8, 13.2) after 3 μg, and 3.6 (1.3, 10.4) and 2.4 (0.2, 33.0) after 6 μg. The GMFR responses among those aged >60 years were 8.1 (2.1, 31.4) and 8.2 (1.2, 57.5) after 3 μg, 2.7 (1.1, 6.7) and 1.8 (0.5, 6.7) after 6 μg, 3.3 (1.5, 7.4) and 3.3 (1.3, 8.0) after 10 μg. The 6 μg dose group in those ≤60 years, 6 μg and 10 μg dose groups in those aged >60 years had higher baseline geometric mean titers (GMTs), which, in turn may have lowered the GMFR for those groups. GMFR persistence until Day 181 in most groups indicated these boosts were associated with durable increases in GMFR. Neutralizing antibody titers assessed via focus reduction neutralization test against SARS-CoV-2 D614G largely mirrored the PsVNA findings.

conclusionsGRT-R910 was safe but reactogenic when administered to previously vaccinated or infected adults and boosted anti-SARS-CoV-2 neutralizing antibody responses in most participants with responses that appeared durable for up to 6 months. CLINICAL

trial registrationhttps://clinicaltrials.gov/study/NCT04776317. CLINICALTRIALS: gov ID NCT04776317.

Indexed as

COVID-19COVID-19 VaccinesImmunization, SecondaryImmunogenicity, VaccineSARS-CoV-2AdolescentAdultAntibodies, NeutralizingAntibodies, ViralEpitopes, T-LymphocyteFemaleHumansMaleMiddle AgedmRNA VaccinesSpike Glycoprotein, CoronavirusAntibodies, NeutralizingAntibodies, ViralCOVID-19 VaccinesEpitopes, T-LymphocyteGRT-R910 vaccinemRNA VaccinesSpike Glycoprotein, Coronavirusspike protein, SARS-CoV-2Vaccines, SyntheticCOVID-19GRT-R10mRNASelf-amplifyingVaccine

Identifiers

PMID41740461
PMCPMC13222540

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.