A Study of mRNA-1647 Cytomegalovirus Vaccine in Healthy Participants 9 to 15 Years of Age and Participants 16 to 25 Years of Age
← catalyst calendarSponsored by ModernaTX, Inc. (industry) · MRNA — their whole pipeline →.
Phase
Phase 1/2
Status
Completed
Study type
Interventional
Design
Randomized · Quadruple · Prevention
Enrollment
873actual
Sites
57
Countries
Canada, United Kingdom, United States
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2022-11-07 | actual | When the study began enrolling |
| Primary completion | 2026-05-12 | actual | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2026-05-12 | actual | The whole study's end, after follow-up |
| First posted | 2022-10-12 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-06-04 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Condition
- Cytomegalovirus
Interventions
- Biological: mRNA-1647
- Other: Placebo
Primary outcomes
what the primary-completion date above is the date OFNumber of Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)
measured Up to Day 176 (7 days after each study injection)
Number of Unsolicited Adverse Events (AEs)
measured Up to Day 197 (28 days after each study injection)
Number of Medically Attended Adverse Events (MAAEs)
measured Up to Day 347 (6 months after the last study injection)
Number of Serious Adverse Events (SAEs), Adverse Events of Special Interest (AESIs), and AEs Leading to Discontinuation
measured Up to Day 527 (end of study)
Geometric Mean Titer (GMT) of Anti-CMV Neutralizing Antibodies (nAbs)
measured Up to Day 527 (end of study)
Geometric Mean Fold-Rise (GMFR) of Anti-CMV nAbs
measured Up to Day 527 (end of study)
Number of Participants with ≥2-Fold, 3-Fold, and 4-Fold increases Over Baseline of Anti-CMV Antibodies
measured Up to Day 527 (end of study)
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