A Phase 3 Study of Revaccination in Subsequent Pregnancies With Bivalent RSV Vaccine and Duration of Protection of a Single Dose
← catalyst calendarNCT06866405 · readout in 554 d
Sponsored by Pfizer (industry) · PFE — their whole pipeline →.
Phase
Phase 3
Status
Recruiting
Study type
Interventional
Design
Randomized · Quadruple · Prevention
Enrollment
550estimated
Sites
96
Countries
Argentina, South Africa, The Gambia +1
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 | 2025-04-16 | actual | When the study began enrolling |
| Primary completion | 2028-02-24 | estimated | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2028-02-24 | estimated | The whole study's end, after follow-up |
| First posted | 2025-03-10 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-08-14 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Condition
- RSV Infection
Interventions
- Biological: RSVpreF
- Biological: Placebo
Primary outcomes
what the primary-completion date above is the date OFPercentage of pregnant participants reporting local reactions
measured From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting systemic events
measured From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting adverse events
measured From Day 1 through 4 weeks after vaccination
Percentage of pregnant participants reporting serious adverse events
measured From Day 1 throughout the study
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting adverse events.
measured From birth through 1 month of age
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting serious adverse events and newly diagnosed medical conditions.
measured From birth through 6 months of age.
Proportion of participants achieving neutralizing antibody to RSV A and RSV B at birth
measured At birth
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