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BEATRIX: group B streptococcus (GBS) vaccine for pregnant women and their babies

A Phase 3, Randomized, Placebo-Controlled, Double-Blinded Trial to Evaluate the Safety, Tolerability, and Immunogenicity of a Multivalent Group B Streptococcus Vaccine in Healthy Pregnant Women and Their Infants

PHASE3 · Pfizer · NCT07160244

This will test a single shot of a 6‑valent group B strep vaccine (or a saline placebo) in healthy pregnant women at 24–36 weeks to see if it's safe and produces protective responses in mothers and their babies.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment6000 (estimated)
Ages1 Day to 49 Years
SexAll
SponsorPfizer (industry)
Locations165 sites (Birmingham, Alabama and 164 other locations)
Trial IDNCT07160244 on ClinicalTrials.gov

What this trial studies

BEATRIX is a randomized, placebo-controlled Phase 3 study giving one dose of a 6‑valent GBS polysaccharide‑conjugate vaccine or saline to healthy pregnant women between 24 0/7 and 36 0/7 weeks of gestation. Participants must have a singleton pregnancy with a normal fetal anatomy ultrasound and documented negative HIV, syphilis, and hepatitis B tests. Mothers and infants are followed through delivery and for up to six months after birth to collect safety data and measure maternal and infant immune responses; infants will receive routine pediatric vaccines such as Infanrix hexa, Prevenar 20, or Pediarix as indicated. Key exclusions include high BMI (>40 kg/m2), current or prior pregnancy complications that raise risk, multiple gestation, or significant fetal anomalies.

Who should consider this trial

Good fit: Healthy pregnant women aged up to 49 years with a singleton pregnancy between 24 0/7 and 36 0/7 weeks, normal fetal ultrasound, negative HIV/syphilis/HBV tests, and willingness to consent for themselves and their infant are ideal candidates.

Not a fit: Women with current pregnancy complications, multiple gestation, BMI over 40 kg/m2, positive HIV/syphilis/HBV tests, major fetal abnormalities, or those randomized to placebo may not receive direct benefit from the vaccine.

Why it matters

Potential benefit: If successful, maternal vaccination could lower newborn GBS infections by passing protective antibodies from mother to baby.

How similar studies have performed: Earlier Phase 1/2 maternal GBS vaccine studies have shown promising safety and immune responses, but larger Phase 3 trials are required to confirm protection for infants.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion criteria- Maternal:

* Healthy pregnant women ≤49 years of age who are between 24 0/7 and 36 0/7 weeks of gestation on the day of planned vaccination, with an uncomplicated, singleton pregnancy, and who have no known increased risk of complications.
* Had a fetal anomaly ultrasound examination with no significant fetal abnormalities observed.
* Documented negative human immunodeficiency virus (HIV) antibody test, syphilis test, and hepatitis B virus (HBV) surface antigen test during this pregnancy and prior to randomization.
* Capable of giving personal signed informed consent.
* Willing to give informed consent for her infant to participate in the study.

Key Exclusion criteria- Maternal:

* Prepregnancy body mass index (BMI) of \>40 kg/m2.
* Current pregnancy complications or abnormalities that may increase the risk associated with the participation in and completion of the study.
* Prior pregnancy complications or abnormalities that, based on the investigator's judgment, may increase the risk associated with the participation in and completion of the study.
* History of microbiologically proven invasive disease caused by GBS in the current pregnancy.
* A known or suspected infection during the current pregnancy that may increase the risk of complications in pregnancy (eg, active tuberculosis, syphilis, primary genital herpes simplex, malaria).

Key Inclusion criteria- Infant Participants

\- Evidence of a signed and dated ICD signed by the parent(s)/legally authorized representative or legal guardian

Key Exclusion Criteria - Infant Participants:

\- Children or grandchildren who are direct descendants of investigator site staff or sponsor and sponsor delegate employees directly involved in the conduct of the study.

Key Exclusion Criteria - Infant immunogenicity subset Participants:

\- Children with a known or suspected contraindication to any vaccine administered in the infant vaccine immunogenicity subset.

Refer to the study contact for further eligibility details

Where this trial is running

Birmingham, Alabama and 164 other locations

+115 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Healthy, group B streptococcus, maternal immunization, vaccine

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.