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NCT Number: NCT07160244

BEATRIX: A Study to Learn About a Group B Streptococcus Vaccine in Healthy Pregnant Women and Their Babies

BEATRIX (group B strEptococcus mATeRnal and Infant VaX study) The purpose of this study is to learn about the safety and how the group B streptococcus (GBS) vaccine works in pregnant women and their babies.

This study is seeking healthy pregnant participants:

* aged 49 or younger who can join. * between 24 and 36 weeks of gestation ("Gestational age" is a medical term used to describe how far along your pregnancy is) * had a fetal ultrasound examination performed with no major fetal abnormalities observed * documented negative for HIV, syphilis and Hepatitis B All participants in this study will receive only 1 shot in an arm. This could either be a group B streptococcus 6-valent polysaccharide conjugate vaccine (GBS6) or placebo. Placebo is an inactive substance used in the study for comparison purposes; in this study, the placebo injection will be saline (saltwater). The pregnant participants may take part in this study for a maximum of 14 months (6 months after delivery) , and their babies for about 12 months after they are born. The pregnant participants will need to visit the research site at least 3 to 4 times with some visits permitted to occur over the telephone.

A subset of infants will be asked to take part in the study for up to 19 months. The subset will receive diphtheria toxoid-containing vaccine and/or pneumococcal vaccine following each country's standard immunization plan and have blood drawn 1 month after completion of the primary and/or toddler (booster) doses.

Recruiting

Interested in participating?

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Key information

Conditions

Healthy

Age range

1 day–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Fundación Respirar, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Multivalent Group B streptococcus vaccine

Biological

Multivalent Group B streptococcus vaccine

Other names: GBS6

Placebo

Biological

Saline Control

Infanrix hexa

Biological

Vaccine administered in a subset of infant participants as per the national immunization schedule

Prevenar 20

Biological

Vaccine administered in a subset of infant participants as per the national immunization schedule

Pediarix

Biological

Vaccine administered in a subset of infant participants as per the national immunization schedule

Prevnar 20

Biological

Vaccine administered in a subset of infant participants as per the national immunization schedule

Infanrix

Biological

Vaccine administered in a subset of infant participants as per the national immunization schedule

Primary outcomes

  1. The proportion of maternal participants reporting prespecified local reactions within 7 days following study intervention

    Time frame: Within 7 days

  2. The proportion of maternal participants reporting prespecified systemic events within 7 days following study intervention

    Time frame: Within 7 days

  3. The proportion of maternal participants reporting adverse events (AEs) through 1 month following study intervention

    Time frame: 1 month

  4. The proportion of maternal participants reporting serious adverse events (SAEs) through 6 months after delivery

    Time frame: 6 months after delivery

  5. The proportion of maternal participants reporting medically attended adverse events (MAAEs) through 6 months after delivery

    Time frame: 6 months after delivery

  6. The proportion of maternal participants reporting adverse events of special interest (AESIs) through 6 months after delivery.

    Time frame: 6 months after delivery

  7. The proportion of infant participants born to pregnant women who were vaccinated with GBS6 during pregnancy reporting adverse events (AEs) from birth through 1 month of age

    Time frame: Birth to 1 month of age

  8. The proportion of infant participants born to pregnant women who were vaccinated with GBS6 during pregnancy reporting serious adverse events (SAEs) from birth through end of the study

    Time frame: Through study completion, at least 1 year

  9. The proportion of infant participants born to pregnant women who were vaccinated with GBS6 during pregnancy reporting medically attended adverse events (MAAEs) from birth through 6 months of age

    Time frame: Birth to 6 months of age

  10. The proportion of infant participants born to pregnant women who were vaccinated with GBS6 during pregnancy reporting adverse events of special interest (AESIs) from birth through end of study

    Time frame: Through study completion, at least 1 year

  11. To measure the relative risk reduction in the proportion of infant participants at birth with GBS serotype-specific IgG antibody concentrations below predefined serotype-specific GBS late onset disease thresholds in the GBS6 group to the placebo group

    Time frame: Birth

  12. To measure the relative risk reduction in the proportion of infant participants at birth with GBS serotype-specific IgG antibody concentrations below predefined serotype-specific GBS early onset disease thresholds in the GBS6 group to the placebo group

    Time frame: Birth

  13. To evaluate the aggregate predicted VE combining all 6 serotypes in GBS6 to provide protection from invasive GBS late onset disease based on serotype specific anti-CPS IgG concentrations measured in infants at birth.

    Time frame: Birth

  14. To evaluate the aggregate predicted VE combining all 6 serotypes in GBS6 to provide protection from invasive GBS early onset disease based on serotype specific anti-CPS IgG concentrations measured in infants at birth.

    Time frame: Birth

Secondary outcomes

  1. To measure GBS serotype-specific opsonophagocytic titers in infant participants at birth by geometric mean ratio between GBS6 group versus placebo group and by the difference in seroresponse rates between GBS6 group and placebo group

    Time frame: Birth

  2. To describe anti-CPS IgG antibody levels predicted to provide protection from invasive GBS disease (all disease) caused by the 6 individual vaccine serotypes in infants when GBS6 is administered to healthy pregnant women.

    Time frame: Birth

  3. To describe anti-CPS IgG antibody levels in infant participants born to maternal participants vaccinated with GBS6.

    Time frame: Birth

  4. To describe anti-CPS IgG antibody levels predicted to provide protection from invasive GBS LOD and EOD, separately, caused by the 6 individual vaccine serotypes (Ia, Ib, II, III, IV, and V) in infants when GBS6 is administered to healthy pregnant women.

    Time frame: Birth

  5. To measure GBS serotype-specific IgG by geometric mean concentration in maternal participants at 1 month after vaccination and at delivery.

    Time frame: 1 month after vaccination and at delivery

  6. Compare the proportion of infants with anti-diphtheria toxoid and/or pneumococcal IgG responses at 1 month post-primary and toddler doses between GBS6 and placebo groups, including predefined IgG levels and geometric mean ratios.

    Time frame: 1 month after the primary vaccination series and 1 month after the toddler dose

Study contacts

Contact information is provided by the study sponsor or research team.

Pfizer CT.gov Call Center

CONTACT

[email protected]

1-800-718-1021

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2028
Study completion
2029
First posted
Sep 8, 2025
Registry last updated
Jul 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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