New mRNA flu shot passes first safety test in humans

NCT ID NCT05446740

Completed ⭐️ VACCINE ⭐️ Sponsor: GlaxoSmithKline Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This early-stage trial tested an experimental mRNA-based flu vaccine in 324 healthy younger (18-45) and older (60-80) adults. The main goal was to check safety and how well the vaccine triggers an immune response. Participants received one of several dose levels or a placebo, and researchers monitored side effects and antibody levels for about two months.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: mRNA-based influenza vaccine (GSK4382276A)
What this could lead to: If successful, this could lead to a new, more effective flu vaccine that uses mRNA technology, potentially offering better protection against influenza.
What could go wrong: This is an early Phase 1 trial with only 324 participants, so safety and immune response are still being tested. The vaccine may not work as hoped or could cause side effects.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

influenza prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

INFLUENZA, HUMAN

Contacts and locations

Locations

GSK Investigational Site

Edegem, 2650, Belgium
GSK Investigational Site

Ghent, 9000, Belgium
GSK Investigational Site

Halifax, Nova Scotia, B3J 3G9, Canada
GSK Investigational Site

Sherbrooke, Quebec, J1L 0H8, Canada
GSK Investigational Site

Madrid, 28006, Spain
GSK Investigational Site

Madrid, 28046, Spain
GSK Investigational Site

Madrid, 28222, Spain

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