Moderna's CMV vaccine shows promise in Long-Term Follow-Up study

NCT ID NCT04975893

Completed ⭐️ VACCINE ⭐️ Sponsor: ModernaTX, Inc. Source: ClinicalTrials.gov ↗

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

Summary

This study is a long-term follow-up of a phase 2 trial testing Moderna's mRNA-1647 vaccine against cytomegalovirus (CMV). It involves 135 adults who previously received the vaccine or a placebo. Researchers are checking how long the immune response lasts and whether a booster dose is safe and effective. The goal is to eventually prevent CMV infection, which can be dangerous for pregnant women and people with weak immune systems.

What this could mean

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

Active substance: mRNA-1647 vaccine
What this could lead to: If successful, this could support the development of a vaccine to prevent cytomegalovirus (CMV) infection, which can cause serious complications in newborns and people with weakened immune systems.
What could go wrong: This is a small, early-phase extension study focused on long-term immune persistence and safety, not on proving the vaccine prevents infection. The results may not confirm effectiveness, and side effects are still being evaluated.

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.

DNA Virus Infections viral infectious disease cytomegalovirus infection prevention target

As listed by the trial registrant

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

CYTOMEGALOVIRUS INFECTION

Contacts and locations

Locations

Alliance for Multispeciality Research, LLC

Lexington, Kentucky, 40509, United States
Crossroads Clinical Research (Victoria)

Victoria, Texas, 77901, United States
J. Lewis Research, Inc. / Foothill Family Clinic South

Salt Lake City, Utah, 84109, United States
J. Lewis Research, Inc. / Foothill Family Clinic South

Salt Lake City, Utah, 84121, United States
Johnson County Clin-Trials, Inc.

Lenexa, Kansas, 66219, United States
Optimal Research, LLC

Peoria, Illinois, 61610, United States
Tekton Research Inc

Austin, Texas, 78745, United States

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