Super-Sized flu shot aims to better shield seniors

NCT ID NCT04498832

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

First seen Jun 25, 2026 · Last updated Jun 26, 2026 · Updated 1 time

Summary

This study tested a high-dose flu vaccine against a standard-dose one in 2,100 adults aged 60 and older in Japan. The goal was to see if the high-dose version triggers a stronger immune response. Participants received one shot and were followed for 28 days to measure antibody levels and safety.

What this could mean

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

Active substance: High-dose quadrivalent influenza vaccine (QIV-HD)
What this could lead to: If successful, this could provide better protection against flu for older adults, who are at higher risk of severe illness.
What could go wrong: This trial is complete, but results may not apply to other populations or flu seasons. A stronger immune response doesn't always mean fewer infections.

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 IMMUNIZATION

Contacts and locations

Locations

Investigational Site Number 3920001

Osaka, Japan
Investigational Site Number 3920002

Suita-Shi, Japan
Investigational Site Number 3920003

Shinjuku-Ku, Japan
Investigational Site Number 3920004

Koganeishi, Japan
Investigational Site Number 3920005

Fukuoka, Japan
Investigational Site Number 3920006

Kumamoto, Japan
Investigational Site Number 3920007

Toshima-Ku, Japan
Investigational Site Number 3920008

Shinjuku-Ku, Japan
Investigational Site Number 3920009

Shinjuku-Ku, Japan
Investigational Site Number 3920010

Yokohama, Japan

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