Sanofi's COVID-19 vaccine shows promise in early trial

NCT ID NCT04537208

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

Summary

This study tested a new COVID-19 vaccine made from a piece of the virus's spike protein, given with or without an immune booster (adjuvant). 441 healthy adults aged 18 and older received one of several vaccine formulas. The goal was to see how well the vaccine triggered an immune response and whether it was safe over 12 months.

What this could mean

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

Active substance

SARS-CoV-2 recombinant protein vaccine with or without adjuvant (AF03 or AS03)

What this could lead to

If successful, this vaccine could help protect against COVID-19 by triggering a strong immune response.

What could go wrong

This is an early-phase trial (Phase 1/2) with only 441 participants, so results may not apply to larger populations. The vaccine may not provide lasting protection or work against new variants.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

COVID-19 prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Investigational Site Number 8400001

    Rochester, New York, 14609, United States

  • Investigational Site Number 8400002

    Omaha, Nebraska, 68134, United States

  • Investigational Site Number 8400003

    Philadelphia, Pennsylvania, 19104, United States

  • Investigational Site Number 8400004

    Birmingham, Alabama, 35294, United States

  • Investigational Site Number 8400007

    Rochester, New York, 14642, United States

  • Investigational Site Number 8400008

    Cleveland, Ohio, 44122, United States

  • Investigational Site Number 8400011

    Hollywood, Florida, 33024, United States

  • Investigational Site Number 8400012

    Rolling Hills Estates, California, 90274, United States

  • Investigational Site Number 8400014

    Mt. Pleasant, South Carolina, 29464, United States

  • Investigational Site Number 8400016

    Boston, Massachusetts, 02115, United States

  • Investigational Site Number 8400019

    Melbourne, Florida, 32934, United States