New flu vaccine candidates show promise in early trial

NCT ID NCT04451954

Completed ⭐️ VACCINE ⭐️ Sponsor: Sanofi Pasteur, a Sanofi Company Source: ClinicalTrials.gov ↗

First seen Jun 24, 2026 · Last updated Jun 26, 2026 · Updated 1 time

Summary

This Phase 1 study tested several versions of a quadrivalent recombinant influenza vaccine, some with an adjuvant, in 210 healthy adults aged 18-30 and 50+. The main goals were to check safety and measure antibody responses against flu strains. Researchers compared different H3 antigens and the effect of adding an adjuvant to see if it boosts immunity.

What this could mean

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

Active substance: Quadrivalent recombinant influenza vaccine with or without adjuvant
What this could lead to: If successful, this could lead to a more effective flu vaccine that provides broader protection against different flu strains.
What could go wrong: This is an early Phase 1 trial focused on safety and immune response, not on preventing flu. The vaccine may not work as well in real-world settings or against future flu strains.

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.

HEALTHY VOLUNTEERS INFLUENZA IMMUNISATION

Contacts and locations

Locations

Investigational Site Number 8400001

Peoria, Illinois, 61614, United States
Investigational Site Number 8400002

Melbourne, Florida, 32934, United States
Investigational Site Number 8400003

San Diego, California, 92108, United States
Investigational Site Number 8400004

Orlando, Florida, 32806, United States
Investigational Site Number 8400005

Rockville, Maryland, 20850, United States

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