Recruiting

Testing Updated COVID-19 Vaccines for Safety and Effectiveness

Plain-English translation of NCT06585241 on ClinicalTrials.gov ↗ · Source last updated March 2026 · Translation generated June 2026 · How we translate trials

Phase 4 — The treatment has already been approved. Researchers are tracking how it works in a large number of people over time.

What is this trial?

This trial is testing updated versions of the mRNA-1273 COVID-19 vaccine — specifically formulations designed to protect against newer virus variants. Researchers want to measure how well your immune system responds to these updated vaccines and confirm they are safe. Different groups will receive different vaccine versions depending on their age and health situation.

As the COVID-19 virus continues to change and produce new variants, scientists need to test whether updated vaccine formulations can keep up and provide better protection. This trial helps determine whether these newer versions are effective and safe for different age groups and populations.

Do you qualify?

You likely qualify if…

you are at least 18 years old (or 6 months old for certain vaccine versions)
you have already received at least one COVID-19 vaccine dose in the past
you are in good health and able to follow study procedures
if you are a woman of childbearing age, you have a negative pregnancy test and agree to use contraception during the study
you do not have a recent COVID-19 infection (within the last 3 to 6 months, depending on the vaccine version)

You likely don't qualify if…

you have had a severe allergic reaction to an mRNA vaccine or any of its ingredients in the past
you recently received another COVID-19 vaccine (within 3 to 6 months, depending on the vaccine version)
you are currently taking medications that suppress your immune system for more than 2 weeks
you have an unstable medical condition that could affect your safety or ability to participate
you are acutely sick or have a fever at the time of enrollment

What participation looks like

You will receive an injection of one of the updated vaccine formulations at a study visit. The study team will monitor you for side effects and ask you about your health at follow-up visits. You will have blood tests to measure how well your immune system responded to the vaccine. The exact length of participation depends on which vaccine version you receive, but the study follows a master protocol that can be updated as new variants emerge.

AI-generated summary from trial data · Jun 15, 2026 · Not medical advice

Trial locations(6 sites)

United States

CenExel, Atlanta, Georgia

CenExel, Decatur, Georgia

Velocity Clinical Research, Baton Rouge, Louisiana

Velocity Clinical Research, Gulfport, Mississippi

Velocity Clinical Research, Omaha, Nebraska