New quadrivalent flu vaccine shows promise in large chinese trial

NCT ID NCT04210349

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

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

Summary

This phase 3 study tested a quadrivalent (four-strain) influenza vaccine against two trivalent (three-strain) vaccines in over 7,100 Chinese participants aged 6 months and older. The goal was to see if the quadrivalent vaccine triggers a stronger immune response and provides broader protection. Researchers also monitored safety, including injection site reactions and serious adverse events.

What this could mean

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

Active substance: Quadrivalent inactivated influenza vaccine
What this could lead to: If successful, this vaccine could provide broader protection against influenza by covering four virus strains instead of three.
What could go wrong: This is a completed phase 3 trial, so results are mature, but the vaccine is specific to strains circulating in China and may not generalize globally. Safety and efficacy data are still limited to this population.

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

Contacts and locations

Locations

Investigational Site Number 1561000

Kunming, 650022, China
Investigational Site Number 1561001

Lincang, 677001, China
Investigational Site Number 1561002

Lincang, 677001, China
Investigational Site Number 1561003

Lincang, 677001, China
Investigational Site Number 1562000

Zhengzhou, 450002, China
Investigational Site Number 1562001

Shangqiu, 476000, China
Investigational Site Number 1562002

Xinxiang, 453200, China

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