New flu vaccine with extra H3 strain shows promise in early trial

NCT ID NCT06507553

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

First seen Jun 26, 2026 · Last updated Jun 26, 2026

Summary

This completed Phase 1 trial tested a new flu vaccine that includes an extra H3 strain, aiming to improve protection against influenza. The study involved 400 healthy adults aged 18-49 and 60+, comparing the new vaccine to standard flu shots. Researchers checked for side effects and measured immune responses over three weeks.

What this could mean

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

Active substance: Influenza vaccine with an extra H3 strain
What this could lead to: If successful, this could lead to a more effective flu vaccine that better protects against certain flu strains, especially for older adults.
What could go wrong: This is an early Phase 1 trial focused on safety and immune response, not yet proven to prevent flu. The extra strain may not improve protection and could cause more 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.

HEALTHY VOLUNTEERS INFLUENZA

Contacts and locations

Locations

Investigational Site Number : 0360001

Melbourne, Victoria, 3124, Australia
Investigational Site Number : 0360002

Botany, New South Wales, 2019, Australia
Investigational Site Number : 0360003

Southport, Queensland, 4222, Australia
Investigational Site Number : 0360004

Sippy Downs, Queensland, 4556, Australia
Investigational Site Number : 0360005

Morayfield, 4506, Australia
Investigational Site Number : 0360007

Adelaide, South Australia, 5067, Australia
Investigational Site Number : 0360010

Brookvale, New South Wales, 2100, Australia
Investigational Site Number : 0360011

Miranda, New South Wales, 2228, Australia
Investigational Site Number : 0360012

Maroubra, New South Wales, 2035, Australia
Investigational Site Number : 0360013

Taringa, Queensland, 4068, Australia

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