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Peer reviewedOpen accessCOVID-19SARS

GRT-R910: a self-amplifying mRNA SARS-CoV-2 vaccine boosts immunity for ≥6 months in previously-vaccinated older adults

Nature Communications·

Christine D. Palmer, Ciaran D. Scallan, Lauren D. Kraemer Tardif, Melissa A. Kachura, Amy R. Rappaport, Daniel O. Koralek, Alison Uriel, Leonid Gitlin, Joshua Klein, Matthew J. Davis, Harshni Venkatraman, Meghan G. Hart, Jason R. Jaroslavsky, Sonia Kounlavouth, Martina Marrali, Charmaine N. Nganje, Kyounghwa Bae, Tiffany Yan, Katharyn Leodones, Milana Egorova, Sue-Jean Hong, Jenchun Kuan, Silvia Grappi, Pedro Garbes, Karin Jooss, Andrew Ustianowski

DOI
10.1038/s41467-023-39053-9
PMID
37280238
PMCID
PMC10242235
OpenAlex
W4379538311
Study type
Journal article
Publisher
Springer Science and Business Media LLC
Article type
journal-article
Integrity
current

Why this research matters now

The vaccine candidate addresses waning humoral immunity observed with authorized vaccines within 6 months of dosing, and targets older populations at higher risk for severe SARS-CoV-2 complications. Durable neutralization and broadened T cell responses may offer extended protection.

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Structured evidence summary

Research question

This phase I trial evaluated the safety, tolerability, and immunogenicity of GRT-R910, a self-amplifying mRNA vaccine encoding SARS-CoV-2 Spike and conserved non-Spike T cell epitopes, as a booster in previously vaccinated healthy older adults.

Study design

Open-label dose-escalation phase I trial with interim analysis. Primary endpoints were safety and tolerability; secondary endpoints assessed immunogenicity through IgG binding, neutralization assays, interferon-gamma ELISpot, and intracellular cytokine staining.

Population and setting

Previously vaccinated healthy older adults enrolled in trial NCT05148962.

Main findings

Most solicited adverse events were mild to moderate and transient, with no treatment-related serious adverse events. Neutralizing antibody titers against ancestral and variant Spike were boosted and persisted through at least 6 months, contrasting with authorized vaccines. GRT-R910 increased Spike-specific T cell responses and primed functional responses to conserved non-Spike epitopes.

Public-health relevance

The vaccine candidate addresses waning humoral immunity observed with authorized vaccines within 6 months of dosing, and targets older populations at higher risk for severe SARS-CoV-2 complications. Durable neutralization and broadened T cell responses may offer extended protection.

Important limitations

The study is limited by small sample size. These are interim findings; additional data from ongoing studies are required to corroborate the results.

GIDS interpretation

This article was indexed under SARS, COVID-19, outbreak investigation, treatment, and vaccination topics, reflecting its focus on vaccine development for SARS-CoV-2 in the context of ongoing public health response. The classifier links support discovery of research on immune durability and novel vaccine platforms.

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Related GIDS surveillance

Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.

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Evidence relationships

This article has 12 auditable classifier relationships to diseases, places, topics, and study design.

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