Super-Sized flu shot shows promise for seniors

NCT ID NCT04537234

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

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

Summary

This study tested a high-dose flu vaccine in 165 healthy adults aged 65 and older in Taiwan. Researchers compared the immune response and safety of the high-dose shot to a standard-dose flu vaccine. The goal was to see if the stronger dose could provide better protection against influenza in older adults, who are at higher risk for severe flu.

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 (Fluzone High Dose / Efluelda)
What this could lead to: If successful, this could show that a high-dose flu vaccine offers better protection for older adults, potentially reducing flu-related hospitalizations and complications.
What could go wrong: This is a completed phase 3 trial, but results may not apply to all populations. The study is relatively small (165 participants) and focused on immune response, not actual prevention of flu illness.

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 (HEALTHY VOLUNTEERS)

Contacts and locations

Locations

Investigational Site Number 1580001

Taipei, 100, Taiwan
Investigational Site Number 1580002

Taipei, 112, Taiwan
Investigational Site Number 1580003

Taoyuan, 333, Taiwan
Investigational Site Number 1580004

Taichung, 40447, Taiwan

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