A Phase 3 Study of Revaccination in Subsequent Pregnancies With Bivalent RSV Vaccine and Duration of Protection of a Single Dose

Last updated: July 1, 2025
Sponsor: Pfizer
Overall Status: Active - Recruiting

Phase

3

Condition

Respiratory Syncytial Virus (Rsv)

Respiratory Syncytial Virus (Rsv) Infection

Treatment

Placebo

RSVpreF

Clinical Study ID

NCT06866405
C3671059
Marguerite
  • All Genders
  • Accepts Healthy Volunteers

Study Summary

This study aims to check how safe and well-tolerated a second dose of RSVpreF is when given during later pregnancies, and to see how long the immunity lasts from a single dose given during a previous pregnancy by examining the blood of nonpregnant participants who had the vaccine before.

Eligibility Criteria

Inclusion

Pregnant Participants-Cohort 1 and Cohort 2 Key Inclusion Criteria

  • Women aged 18 to 49 who are pregnant, between 24 and 36 weeks along, and expecting one baby without known risks for complications can participate.

  • Had the RSVpreF or Abrysvo vaccine during a previous pregnancy.

  • Had an ultrasound scan at 18 weeks or later during their current pregnancy, with no major fetal problems detected.

  • Based on their medical history, physical check-up, and the doctor's judgment, they are found suitable to join the study.

  • Agrees to let their baby take part in the study and gives their permission.

  • Able to sign a consent form, agreeing to follow the rules and conditions of the study.

Key Exclusion Criteria

  • Received any approved or experimental RSV vaccine since their previous pregnancy.

  • Has a pre-pregnancy body mass index (BMI) over 40 kg/m2.

  • History of a severe bad reaction to a vaccine or a serious allergic reaction (like anaphylaxis) to any ingredient in the study vaccine or a similar vaccine.

  • Current pregnancy problems or issues at the time of giving consent.

  • Previous pregnancy issues or problems at the time of giving consent.

Infant Participants

  • Proof that the parent(s) or legal guardian(s) has signed and dated a consent form.

  • Parent(s) or legal guardian(s) must agree to attend scheduled visits and follow the study plan, including laboratory tests and other procedures.

Nonpregnant Participants-Cohort 3 Key Inclusion Criteria

  • Have already received one dose of the RSVpreF vaccine during their previous pregnancy as part of the Pfizer clinical trial, and the results from that time can be used for this study.

  • Able to sign a consent form, agreeing to follow the rules and requirements of the study.

Key Exclusion Criteria

  • Received any approved or experimental RSV vaccine after participating in the Pfizer clinical trial.

  • Taking part in other studies with new drugs within 28 days before giving consent or during the study period.

Study Design

Total Participants: 550
Treatment Group(s): 2
Primary Treatment: Placebo
Phase: 3
Study Start date:
April 16, 2025
Estimated Completion Date:
February 24, 2028

Study Description

This study will include pregnant participants and their unborn babies (Cohort 1 and Cohort 2) and non-pregnant participants (Cohort 3), as described below:

  • Cohort 1- Pregnant participants who had previously received RSVpreF as part of a Pfizer clinical trial and have antibody data available from that trial will get a second dose of RSVpreF.

  • Cohort 2- Pregnant participants who received the RSVpreF in a previous pregnancy, either through commercial means with Abrysvo® or as part of a Pfizer clinical trial, will be randomly chosen to get either one dose of the RSVpreF or one dose of a placebo. This applies to those who do not have antibody data available from the earlier trial.

For both groups of pregnant participants, the study will look at how safe and well-tolerated the vaccine is during pregnancy, as well as how the body responds to it.

Infants will be monitored for six months after birth to check safety and antibodies level.

• Cohort 3- Nonpregnant participants who received RSVpreF during a previous pregnancy as part of an earlier clinical trial will have blood samples taken to see how well their immune response has persisted over time. Participants will not receive any vaccine.

Connect with a study center

  • Lucile Packard Children's Hospital

    Palo Alto, California 94304
    United States

    Site Not Available

  • Lucile Packard Children's Hospital-Labor and Delivery Unit

    Palo Alto, California 94304
    United States

    Site Not Available

  • Stanford University

    Palo Alto, California 94304
    United States

    Site Not Available

  • Stanford University Medical Center

    Palo Alto, California 94304
    United States

    Site Not Available

  • Emerald Coast OBGYN Clinical Research

    Panama City, Florida 32405
    United States

    Site Not Available

  • Emerald Coast Pediatrics

    Panama City, Florida 32405
    United States

    Site Not Available

  • HCA Florida Gulf Coast Hospital

    Panama City, Florida 32405
    United States

    Site Not Available

  • Emerald Coast Pediatrics

    Panama City Beach, Florida 32407
    United States

    Site Not Available

  • Advanced Specialty Research

    Boise, Idaho 83702
    United States

    Active - Recruiting

  • Saint Alphonsus Regional Medical Center

    Boise, Idaho 83706
    United States

    Active - Recruiting

  • St. Luke's Boise Medical Center

    Boise, Idaho 83712
    United States

    Active - Recruiting

  • Clinical Research Prime

    Idaho Falls, Idaho 83404
    United States

    Active - Recruiting

  • Saint Alphonsus Medical Center

    Nampa, Idaho 83687
    United States

    Active - Recruiting

  • St. Luke's Nampa Medical Center

    Nampa, Idaho 83687
    United States

    Active - Recruiting

  • Velocity Clinical Research, Lafayette

    Lafayette, Louisiana 70508
    United States

    Site Not Available

  • Velocity Clinical Research - New Orleans

    New Orleans, Louisiana 70119
    United States

    Active - Recruiting

  • Boston Medical Center

    Boston, Massachusetts 02118
    United States

    Site Not Available

  • Velocity Clinical Research, Gulfport

    Gulfport, Mississippi 39503
    United States

    Site Not Available

  • Boeson Research GTF

    Great Falls, Montana 59405
    United States

    Active - Recruiting

  • OBGYN Associates

    Great Falls, Montana 59405
    United States

    Active - Recruiting

  • Boeson Research KAL

    Kalispell, Montana 59901
    United States

    Active - Recruiting

  • Heart & Hands Midwifery

    Kalispell, Montana 59901
    United States

    Active - Recruiting

  • Boeson Research Laboratory

    Missoula, Montana 59804
    United States

    Site Not Available

  • Boeson Research MSO

    Missoula, Montana 59804
    United States

    Active - Recruiting

  • Origin Health

    Missoula, Montana 59804
    United States

    Active - Recruiting

  • Velocity Clinical Research, Grand Island

    Grand Island, Nebraska 68803
    United States

    Active - Recruiting

  • Velocity Clinical Research, Norfolk

    Norfolk, Nebraska 68701
    United States

    Active - Recruiting

  • Lovelace Women's Hospital

    Albuquerque, New Mexico 87109
    United States

    Active - Recruiting

  • Presbyterian Hospital

    Albuquerque, New Mexico 87107
    United States

    Active - Recruiting

  • UNM Hospital

    Albuquerque, New Mexico 87107
    United States

    Active - Recruiting

  • Velocity Clinical Research, Albuquerque

    Albuquerque, New Mexico 87107
    United States

    Active - Recruiting

  • Memorial Hermann Memorial City Hospital

    Houston, Texas 77024
    United States

    Active - Recruiting

  • The University of Texas Health Science Center at Houston

    Houston, Texas 77204
    United States

    Active - Recruiting

  • Sentara Leigh Hospital

    Norfolk, Virginia 23502
    United States

    Active - Recruiting

  • The Group For Women - Kempsville Office

    Norfolk, Virginia 23502
    United States

    Active - Recruiting

  • Tidewater Physicians for Women

    Norfolk, Virginia 23502
    United States

    Active - Recruiting

  • WomensCare Center

    Norfolk, Virginia 23502
    United States

    Active - Recruiting

  • Virginia Physicians For Women (VPFW)

    North Chesterfield, Virginia 23235
    United States

    Active - Recruiting

  • Clinical Research Partners, LLC

    Richmond, Virginia 23226
    United States

    Active - Recruiting

  • Infusion Solutions, LLC

    Richmond, Virginia 23226
    United States

    Active - Recruiting

Not the study for you?

Let us help you find the best match. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.