New variant-targeted COVID boosters show promise in large trial

NCT ID NCT05289037

Completed ⭐️ VACCINE ⭐️ Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This Phase 2 trial tested updated mRNA vaccines designed to target specific COVID-19 variants, including Omicron. Over 1,200 adults who were already vaccinated received one or two doses of these variant vaccines. The goal was to see if these updated shots could boost the immune system's ability to recognize and fight new and emerging variants.

What this could mean

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

Active substance: mRNA vaccines (original and variant-specific) with or without an adjuvant (AS03)
What this could lead to: If successful, this could help design booster shots that better protect against emerging COVID-19 variants.
What could go wrong: This is a Phase 2 trial, so results are still early. The variant-specific vaccines may not offer significantly better protection than existing boosters, and immune responses can vary.

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.

COVID-19 prevention target

As listed by the trial registrant

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

COVID-19

Contacts and locations

Locations

Baylor College of Medicine

Houston, Texas, 77030-3411, United States
Brigham and Women's Hospital

Boston, Massachusetts, 02115-6110, United States
Duke Vaccine and Trials Unit

Durham, North Carolina, 27703, United States
Emory University School of Medicine

Atlanta, Georgia, 30322-1013, United States
George Washington University Medical Faculty Associates

Washington D.C., District of Columbia, 20037-3201, United States
Howard University - Department of Medicine - Division of Infectious Disease

Washington D.C., District of Columbia, 20060, United States
Kaiser Permanente Washington Health Research Institute

Seattle, Washington, 98101, United States
Morehouse School of Medicine - Clinical Research Center

Atlanta, Georgia, 30310, United States
NYU Grossman School, NYU Langone Vaccine Center, Long Island

Mineola, New York, 11501, United States
NYU Langone Vaccine Center Research Clinic, Manhattan

New York, New York, 10016, United States
Saint Louis University Center for Vaccine Development

St Louis, Missouri, 63104-1015, United States
The Hope Clinic of Emory University

Decatur, Georgia, 30030-1705, United States
The University of Washington - Virology Research Clinic

Seattle, Washington, 98104, United States
Tulane University Clinical Translational Unit

New Orleans, Louisiana, 70112, United States
University of Alabama at Birmingham School of Medicine - Alabama Vaccine Research Clinic

Birmingham, Alabama, 35294, United States
University of California, San Diego (UCSD) - Antiviral Research Center (AVRC)

San Diego, California, 92103-8208, United States
University of Illinois at Chicago College of Medicine - Division of Infectious Diseases

Chicago, Illinois, 60612, United States
University of Iowa Hospitals & Clinics - Department of Internal Medicine

Iowa City, Iowa, 52242, United States
University of Rochester Medical Center - Vaccine Research Unit

Rochester, New York, 14611-3201, United States
University of Texas Medical Branch

League City, Texas, 77573, United States
Washington University School of Medicine in St. Louis - Infectious Disease Clinical Research Unit

St Louis, Missouri, 63110, United States
Zuckerberg San Francisco General Hospital, UCSF Positive Health Program

San Francisco, California, 94110, United States

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