Group B Streptococcus InfectionsPhase 2NCT04766086

Trial to Evaluate the Safety, Tolerability, and Immunogenicity of A Multivalent Group B Streptococcus Vaccine When Administered Concomitantly With Tdap in Healthy Nonpregnant Women

A Phase 2 study testing Multivalent Group B streptococcus vaccine and Tetanus, diphtheria, and acellular pertussis vaccine in people with Group B Streptococcus Infections, run by Pfizer at 12 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

This phase 2B, placebo-controlled, randomized, observer-blinded trial will evaluate the safety, tolerability, and immunogenicity of the investigational multivalent group B streptococcus vaccine administered concomitantly with Tdap in healthy nonpregnant women 18 through 49 years of age. Read more about this study

Who is it for?: Ages 18 to 49 years, women onlyHealthy volunteers can take part
Conditions the study is for: Group B Streptococcus Infections
What is being tested?: Multivalent Group B streptococcus vaccine and Tetanus, diphtheria, and acellular pertussis vaccine
Type of treatment: Vaccines
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 306 participants
Where: 12 sitesUnited States
Study dates: 12 Aug 2022to 27 Apr 2023
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 49 years
Women only
Healthy volunteers accepted
Adult

Who may be able to join

Healthy women ≥18 and ≤49 years of age.
Participants who are willing and able to comply with scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures, including completion of the e-diary from Day 1 to Day 7 following administration of investigational product.
Healthy females at enrollment who are determined by medical history, physical examination, and clinical judgment of the investigator to be eligible for inclusion in the study.
Expected to be available for the duration of the study and who can be contacted by telephone during study participation.
Capable of giving personal signed informed consent.

Who cannot join

Pregnant female participants; breastfeeding female participants; positive urine pregnancy test for women of childbearing potential (WOCBP) at Visit 1 (prior to vaccination)
History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the investigational product or any diphtheria toxoid-containing or CRM197-containing vaccine.
History of microbiologically proven invasive disease caused by group B streptococcus.
Immunocompromised participants with known or suspected immunodeficiency.
Bleeding diathesis or condition associated with prolonged bleeding that would in the opinion of the investigator contraindicate intramuscular injection.
Other acute or chronic medical or psychiatric condition, including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.

Show all 12Show fewer

Previous vaccination with any licensed or investigational GBS vaccine, or planned receipt during the participant's participation in the study (through the 1-month follow-up visit [Visit 2]).
Vaccination within 5 years with tetanus and diphtheria toxoids and acellular pertussis-containing vaccines (Tdap) before investigational product administration.
Participants who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids
Vaccination with diphtheria- or CRM197-containing vaccine(s) from 6 months before investigational product administration, or planned receipt through the 1-month follow-up visit.
Receipt or planned receipt of blood/plasma products or immunoglobulin, from 60 days before investigational product administration through the 1-month follow-up visit
Participation in other studies involving investigational drug(s) within 28 days prior to study entry and/or during study participation

Trial locations and contacts

12 sites in 1 country.

City, postcode or hospital

12 sites in 1 country

United States12 sites

PriMED Clinical Research
Dayton, Ohio, 45419
PriMed Clinical Research
Dayton, Ohio, 45429
Benchmark Research
Fort Worth, Texas, 76135
DM Clinical Research - Brookline
Houston, Texas, 77081
Alliance for Multispecialty Research, LLC
Knoxville, Tennessee, 37909
Alliance for Multispecialty Research, LLC
Las Vegas, Nevada, 89119
Alliance for Multispecialty Research, LLC
Newton, Kansas, 67114
Lynn Health Science Institute
Oklahoma City, Oklahoma, 73112
Quality Clinical Research, Inc
Omaha, Nebraska, 68114
Accellacare - Raleigh
Raleigh, North Carolina, 27609
J. Lewis Research, Inc. / Foothill Family Clinic South
Salt Lake City, Utah, 84121
Accellacare - Wilmington
Wilmington, North Carolina, 28401

Other trials in United States

About this study

Official title: A PHASE 2B, PLACEBO-CONTROLLED, RANDOMIZED, OBSERVER-BLINDED TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A MULTIVALENT GROUP B STREPTOCOCCUS VACCINE WHEN ADMINISTERED CONCOMITANTLY WITH TETANUS, DIPHTHERIA, AND ACELLULAR PERTUSSIS VACCINE (TDAP) IN HEALTHY NONPREGNANT WOMEN 18 THROUGH 49 YEARS OF AGE

Conditions: Group B Streptococcus Infections
Being tested: Multivalent Group B streptococcus vaccine, Tetanus, diphtheria, and acellular pertussis vaccine, Placebo

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Multivalent Group B streptococcus vaccineBiological
Multivalent Group B streptococcus vaccine
Tetanus, diphtheria, and acellular pertussis vaccineBiological
Also called Tdap
Tetanus, diphtheria, and acellular pertussis vaccine
PlaceboBiological
Saline control

Study groups in NCT04766086
Study group	Role	What they receive
GBS6 and Tdap	Experimental	Multivalent group B streptococcus vaccine and Tetanus, diphtheria, and acellular pertussis vaccine (Tdap) Receives: Biological: Multivalent Group B streptococcus vaccine; Biological: Tetanus, diphtheria, and acellular pertussis vaccine
GBS6 and Placebo	Experimental	Multivalent group B streptococcus vaccine and Placebo Receives: Biological: Multivalent Group B streptococcus vaccine; Biological: Placebo
Placebo and Tdap	Experimental	Placebo and Tetanus, diphtheria, and acellular pertussis vaccine (Tdap) Receives: Biological: Tetanus, diphtheria, and acellular pertussis vaccine; Biological: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Percentage of Participants Reporting Local Reactions Within 7 Days After Vaccination
Local reactions (redness, swelling, and pain at the injection site of the left arm) were recorded by participants in e-diary. Erythema/Redness and induration/swelling were measured and recorded in measuring device units (1 measuring device unit=0.5 centimeter [cm]). Grading: Grade 1/mild (greater than [>] 2.0 to 5.0 cm), Grade 2/moderate (>5.0 to 10.0 cm), Grade 3/severe (>10.0 cm) and Grade 4 (necrosis [swelling] or necrosis or exfoliative dermatitis [redness]). Pain at injection site was graded as Grade 1/mild (did not interfere with activity), Grade2/moderate (interfered with activity), Grade 3/severe (prevented daily activity) and Grade 4 (emergency room [ER] visit or hospitalization for severe pain at injection site). Grade 4 were classified by investigator or medically qualified person.
Measured: Day 1 (day of vaccination) to Day 7
Percentage of Participants Reporting Systemic Reactions Within 7 Days After Vaccination
Systemic events were recorded in e-diary. Fever: oral temperature greater than or equal to (>=) 38.0 degree Celsius (deg C) and categorized as >=38.0-38.4 deg C, >38.4-38.9 deg C, >38.9-40.0 deg C and >40.0 deg C. Nausea/vomiting was graded as: Grade 1/mild (1-2 times in 24 hours [h]), Grade 2/moderate: (>2 times in 24h), Grade 3/severe (required intravenous hydration) and Grade 4 (ER visit/hospitalization for hypotensive shock). Diarrhea was graded as: Grade 1/mild (2-3 loose stools in 24h), Grade 2/moderate (4-5 loose stools in 24h), Grade 3/severe (6 or more loose stools in 24h) and Grade 4 (ER visit/hospitalization for severe diarrhea). Fatigue/tiredness, headache, chills, muscle pain and joint pain were graded as: Grade 1/mild (did not interfere with activity), Grade 2/moderate (some interference with activity), Grade 3/severe (prevented daily routine activity) and Grade 4 (ER visit/hospitalization). Grade 4 were classified by investigator or medically qualified person.
Measured: Day 1 (day of vaccination) to Day 7
Percentage of Participants Reporting Adverse Events (AEs) Through 1 Month After Vaccination
An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. In this outcome measure results excluded data for local reactions and systemic events.
Measured: Day 1 (day of vaccination) through 1 Month post-vaccination
Percentage of Participants Reporting Medically Attended Adverse Events (MAEs) and Serious Adverse Events (SAEs) Through 6 Months After Vaccination
A MAE was defined as a non-serious AE that resulted in an evaluation at a medical facility. A SAE was defined as any untoward medical occurrence at any dose that resulted in any of the following outcomes: death; life-threatening (immediate risk of death); required inpatient hospitalization or prolongation of existing hospitalization; persistent or significant disability/incapacity (substantial disruption of the ability to conduct normal life functions); congenital anomaly/birth defect; or that was considered as an important medical event.
Measured: Day 1 (day of vaccination) through 6 Months post-vaccination
Percentage of Participants Achieving Anti-tetanus Toxoid (Anti-TTd) and Anti-diphtheria Toxoid (Anti-DTd) Antibody Concentration >=0.1 IU/mL at 1 Month After Vaccination: GBS6 + Tdap and Placebo + Tdap Groups
IU/mL stands for international units per milliliter.
Measured: 1 Month after Vaccination (Day 1, day of vaccination)
Geometric Mean Concentration (GMC) of Anti-Pertussis Toxin (PT), Anti-Filamentous Hemagglutinin (FHA), and Anti-Pertactin (PRN) Antibodies; GMR of Anti-PT, Anti-FHA, and Anti-PRN for GBS6 + Tdap to Placebo + Tdap at 1 Month After Vaccination
GMCs of anti-PT, anti-FHA, and anti-PRN was reported as descriptive data for the GBS6 +Tdap and placebo + Tdap groups, along with associated 2-sided 95% confidence interval. GMR for anti-PT, anti-FHA and anti-PRN antibodies were estimated from the GBS6 + Tdap group to the placebo + Tdap group and reported as statistical data.
Measured: 1 Month after Vaccination (Day 1, day of vaccination)
GMC of GBS Capsular Polysaccharide (CPS) Serotype-Specific Immunoglobulin G (IgG) Antibodies; GMR of GBS CPS Serotype-specific IgG Antibodies for GBS6 + Tdap to Placebo + Tdap at 1 Month After Vaccination
GBS CPS serotype-specific IgG GMCs (Ia, Ib, II, III, IV, V) were reported as descriptive data for the GBS6+Tdap and GBS6+placebo groups, along with associated 2-sided 95% confidence interval. GMR of GBS CPS serotype-specific IgG antibodies were estimated from the GBS6 + Tdap group to the placebo + Tdap group and reported as statistical data.
Measured: 1 Month after Vaccination (Day 1, day of vaccination)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

12 Aug 202227 Apr 2023

First posted23 Feb 2021
Study start12 Aug 2022
Primary completion27 Apr 2023
Study completion27 Apr 2023

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Group B Streptococcus InfectionsStudies of the same condition, open and under way.
More trials run by PfizerThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind
Who is masked: Participant, Investigator
Enrolment: 306 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04766086
Sponsor's protocol ID: C1091005
Status last verified: Apr 2024
First submitted: 18 Feb 2021
Last updated: 24 May 2024
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.

Publications

Smith WB, Seger W, Chawana R, Skogeby Z, Silmon de Monerri NC, Feng Y, Gaylord M, Jongihlati B, Beeslaar J, Skinner JM, Bickham K, Anderson AS. A Phase 2b Trial Evaluating the Safety, Tolerability, and Immunogenicity of a 6-Valent Group B Streptococcus Vaccine Administered Concomitantly With Tetanus, Diphtheria, and Acellular Pertussis Vaccine in Healthy Nonpregnant Female Individuals. J Infect Dis. 2025 Jul 11;231(6):e1065-e1074. doi: 10.1093/infdis/jiaf096.
PubMed 40036340

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 24 May 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A PHASE 2B, PLACEBO-CONTROLLED, RANDOMIZED, OBSERVER-BLINDED TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A MULTIVALENT GROUP B STREPTOCOCCUS VACCINE WHEN ADMINISTERED CONCOMITANTLY WITH TETANUS, DIPHTHERIA, AND ACELLULAR PERTUSSIS VACCINE (TDAP) IN HEALTHY NONPREGNANT WOMEN 18 THROUGH 49 YEARS OF AGE
ClinicalTrials.gov ID: NCT04766086
Acronym / sponsor ID: C1091005
Conditions: Group B Streptococcus Infections
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 306 participants (actual)
Lead sponsor: PfizerIndustry (pharma, biotech, devices)
Study start: 12 Aug 2022 (actual)
Primary completion: 27 Apr 2023 (actual)
Study completion: 27 Apr 2023 (actual)
First posted: 23 Feb 2021 (actual)
Results: Posted 24 May 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind (participant, investigator)
Number of arms: 3

Arm	Type	Receives
GBS6 and Tdap	Experimental	Biological: Multivalent Group B streptococcus vaccine, Biological: Tetanus, diphtheria, and acellular pertussis vaccineMultivalent group B streptococcus vaccine and Tetanus, diphtheria, and acellular pertussis vaccine (Tdap)
GBS6 and Placebo	Experimental	Biological: Multivalent Group B streptococcus vaccine, Biological: PlaceboMultivalent group B streptococcus vaccine and Placebo
Placebo and Tdap	Experimental	Biological: Tetanus, diphtheria, and acellular pertussis vaccine, Biological: PlaceboPlacebo and Tetanus, diphtheria, and acellular pertussis vaccine (Tdap)

Who may qualify

Ages: 18 to 49 years
Sex: Female only
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (5 listed)

Healthy women ≥18 and ≤49 years of age.
Participants who are willing and able to comply with scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures, including completion of the e-diary from Day 1 to Day 7 following administration of investigational product.
Healthy females at enrollment who are determined by medical history, physical examination, and clinical judgment of the investigator to be eligible for inclusion in the study.
Expected to be available for the duration of the study and who can be contacted by telephone during study participation.
Capable of giving personal signed informed consent.

Key exclusion criteria (12 listed)

Pregnant female participants; breastfeeding female participants; positive urine pregnancy test for women of childbearing potential (WOCBP) at Visit 1 (prior to vaccination)
History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the investigational product or any diphtheria toxoid-containing or CRM197-containing vaccine.
History of microbiologically proven invasive disease caused by group B streptococcus.
Immunocompromised participants with known or suspected immunodeficiency.
Bleeding diathesis or condition associated with prolonged bleeding that would in the opinion of the investigator contraindicate intramuscular injection.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Multivalent Group B streptococcus vaccineMultivalent Group B streptococcus vaccine	Biological	GBS6 and Placebo, GBS6 and Tdap
Tetanus, diphtheria, and acellular pertussis vaccineAlso: TdapTetanus, diphtheria, and acellular pertussis vaccine	Biological	GBS6 and Tdap, Placebo and Tdap
PlaceboSaline control	Biological	GBS6 and Placebo, Placebo and Tdap

Primary outcome

Percentage of Participants Reporting Local Reactions Within 7 Days After Vaccination
Time frame: Day 1 (day of vaccination) to Day 7
Local reactions (redness, swelling, and pain at the injection site of the left arm) were recorded by participants in e-diary. Erythema/Redness and induration/swelling were measured and recorded in measuring device units (1 measuring device unit=0.5 centimeter [cm]). Grading: Grade 1/mild (greater than [>] 2.0 to 5.0 cm), Grade 2/moderate (>5.0 to 10.0 cm), Grade 3/severe (>10.0 cm) and Grade 4 (necrosis [swelling] or necrosis or exfoliative dermatitis [redness]). Pain at injection site was graded as Grade 1/mild (did not interfere with activity), Grade2/moderate (interfered with activity), Grade 3/severe (prevented daily activity) and Grade 4 (emergency room [ER] visit or hospitalization for severe pain at injection site). Grade 4 were classified by investigator or medically qualified person.
Percentage of Participants Reporting Systemic Reactions Within 7 Days After Vaccination
Time frame: Day 1 (day of vaccination) to Day 7
Systemic events were recorded in e-diary. Fever: oral temperature greater than or equal to (>=) 38.0 degree Celsius (deg C) and categorized as >=38.0-38.4 deg C, >38.4-38.9 deg C, >38.9-40.0 deg C and >40.0 deg C. Nausea/vomiting was graded as: Grade 1/mild (1-2 times in 24 hours [h]), Grade 2/moderate: (>2 times in 24h), Grade 3/severe (required intravenous hydration) and Grade 4 (ER visit/hospitalization for hypotensive shock). Diarrhea was graded as: Grade 1/mild (2-3 loose stools in 24h), Grade 2/moderate (4-5 loose stools in 24h), Grade 3/severe (6 or more loose stools in 24h) and Grade 4 (ER visit/hospitalization for severe diarrhea). Fatigue/tiredness, headache, chills, muscle pain and joint pain were graded as: Grade 1/mild (did not interfere with activity), Grade 2/moderate (some interference with activity), Grade 3/severe (prevented daily routine activity) and Grade 4 (ER visit/hospitalization). Grade 4 were classified by investigator or medically qualified person.
Percentage of Participants Reporting Adverse Events (AEs) Through 1 Month After Vaccination
Time frame: Day 1 (day of vaccination) through 1 Month post-vaccination
An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. In this outcome measure results excluded data for local reactions and systemic events.
Percentage of Participants Reporting Medically Attended Adverse Events (MAEs) and Serious Adverse Events (SAEs) Through 6 Months After Vaccination
Time frame: Day 1 (day of vaccination) through 6 Months post-vaccination
A MAE was defined as a non-serious AE that resulted in an evaluation at a medical facility. A SAE was defined as any untoward medical occurrence at any dose that resulted in any of the following outcomes: death; life-threatening (immediate risk of death); required inpatient hospitalization or prolongation of existing hospitalization; persistent or significant disability/incapacity (substantial disruption of the ability to conduct normal life functions); congenital anomaly/birth defect; or that was considered as an important medical event.
Percentage of Participants Achieving Anti-tetanus Toxoid (Anti-TTd) and Anti-diphtheria Toxoid (Anti-DTd) Antibody Concentration >=0.1 IU/mL at 1 Month After Vaccination: GBS6 + Tdap and Placebo + Tdap Groups
Time frame: 1 Month after Vaccination (Day 1, day of vaccination)
IU/mL stands for international units per milliliter.
Geometric Mean Concentration (GMC) of Anti-Pertussis Toxin (PT), Anti-Filamentous Hemagglutinin (FHA), and Anti-Pertactin (PRN) Antibodies; GMR of Anti-PT, Anti-FHA, and Anti-PRN for GBS6 + Tdap to Placebo + Tdap at 1 Month After Vaccination
Time frame: 1 Month after Vaccination (Day 1, day of vaccination)
GMCs of anti-PT, anti-FHA, and anti-PRN was reported as descriptive data for the GBS6 +Tdap and placebo + Tdap groups, along with associated 2-sided 95% confidence interval. GMR for anti-PT, anti-FHA and anti-PRN antibodies were estimated from the GBS6 + Tdap group to the placebo + Tdap group and reported as statistical data.
GMC of GBS Capsular Polysaccharide (CPS) Serotype-Specific Immunoglobulin G (IgG) Antibodies; GMR of GBS CPS Serotype-specific IgG Antibodies for GBS6 + Tdap to Placebo + Tdap at 1 Month After Vaccination
Time frame: 1 Month after Vaccination (Day 1, day of vaccination)
GBS CPS serotype-specific IgG GMCs (Ia, Ib, II, III, IV, V) were reported as descriptive data for the GBS6+Tdap and GBS6+placebo groups, along with associated 2-sided 95% confidence interval. GMR of GBS CPS serotype-specific IgG antibodies were estimated from the GBS6 + Tdap group to the placebo + Tdap group and reported as statistical data.

Results and safety

Results posted to the registry on 24 May 2024, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
GBS6 + Tdap	103	99
GBS6 + Placebo	99	93
Placebo + Tdap	104	98

Primary outcome: Percentage of Participants Reporting Local Reactions Within 7 Days After Vaccination

Time frame: Day 1 (day of vaccination) to Day 7. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	GBS6 + Tdap n = 102	GBS6 + Placebo n = 98	Placebo + Tdap n = 103
Pain at injection site: Any	39.2 (29.7 to 49.4)	45.9 (35.8 to 56.3)	33.0 (24.1 to 43.0)
Pain at injection site: Mild	27.5 (19.1 to 37.2)	35.7 (26.3 to 46.0)	26.2 (18.0 to 35.8)
Pain at injection site: Moderate	11.8 (6.2 to 19.6)	9.2 (4.3 to 16.7)	6.8 (2.8 to 13.5)
Pain at injection site: Severe	0 (0.0 to 3.6)	1.0 (0.0 to 5.6)	0 (0.0 to 3.5)
Pain at injection site: Grade 4	0 (0.0 to 3.6)	0 (0.0 to 3.7)	0 (0.0 to 3.5)
Erythema/redness: Any	7.8 (3.4 to 14.9)	2.0 (0.2 to 7.2)	0 (0.0 to 3.5)
Erythema/redness: Mild	4.9 (1.6 to 11.1)	1.0 (0.0 to 5.6)	0 (0.0 to 3.5)
Erythema/redness: Moderate	2.9 (0.6 to 8.4)	1.0 (0.0 to 5.6)	0 (0.0 to 3.5)

Population analysed: Safety set included all participants who received at least 1 dose of the study interventions and had at least 1 valid post dose safety assessment. Here, "Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Primary outcome: Percentage of Participants Reporting Systemic Reactions Within 7 Days After Vaccination

Time frame: Day 1 (day of vaccination) to Day 7. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	GBS6 + Tdap n = 102	GBS6 + Placebo n = 99	Placebo + Tdap n = 103
Fever: >= 38.0°C	1.0 (0.0 to 5.3)	4.0 (1.1 to 10.1)	2.9 (0.6 to 8.3)
Fever: 38.0°C to 38.4°C	0 (0.0 to 3.6)	2.0 (0.2 to 7.2)	2.9 (0.6 to 8.3)
Fever: >38.4°C to 38.9°C	1.0 (0.0 to 5.3)	0 (0.0 to 3.7)	0 (0.0 to 3.5)
Fever: >38.9°C to 40.0°C	0 (0.0 to 3.6)	2.0 (0.2 to 7.2)	0 (0.0 to 3.5)
Fever: >40.0°C	0 (0.0 to 3.6)	0 (0.0 to 3.7)	0 (0.0 to 3.5)
Nausea/vomiting: Any	14.7 (8.5 to 23.1)	17.2 (10.4 to 26.3)	14.6 (8.4 to 22.9)
Nausea/vomiting: Mild	7.8 (3.4 to 14.9)	12.1 (6.5 to 20.4)	12.6 (6.9 to 20.6)
Nausea/vomiting: Moderate	6.9 (2.8 to 13.6)	5.1 (1.7 to 11.5)	1.9 (0.2 to 6.8)

Population analysed: Safety set included all participants who received at least 1 dose of the study interventions and had at least 1 valid post dose safety assessment.

Primary outcome: Percentage of Participants Reporting Adverse Events (AEs) Through 1 Month After Vaccination

Time frame: Day 1 (day of vaccination) through 1 Month post-vaccination. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	GBS6 + Tdap n = 102	GBS6 + Placebo n = 99	Placebo + Tdap n = 103
Value	5.9 (2.2 to 12.4)	8.1 (3.6 to 15.3)	3.9 (1.1 to 9.6)

Population analysed: Safety set included all participants who received at least 1 dose of the study interventions and had at least 1 valid post dose safety assessment.

Primary outcome: Percentage of Participants Reporting Medically Attended Adverse Events (MAEs) and Serious Adverse Events (SAEs) Through 6 Months After Vaccination

Time frame: Day 1 (day of vaccination) through 6 Months post-vaccination. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	GBS6 + Tdap n = 102	GBS6 + Placebo n = 99	Placebo + Tdap n = 103
MAEs	4.9 (1.6 to 11.1)	4.0 (1.1 to 10.0)	6.8 (2.8 to 13.5)
SAEs	0 (0.0 to 3.6)	0 (0.0 to 3.7)	1.0 (0.0 to 5.3)

Population analysed: Safety set included all participants who received at least 1 dose of the study interventions and had at least 1 valid post dose safety assessment.

Adverse events

Time frame: Local reaction and systemic events (systematic assessment): up to 7 days post-vaccination; All-cause mortality, SAEs, MAEs (non-systematic assessment): up to 6 months post-vaccination; Other AEs (non-systematic assessment): up to 1-month post-vaccination [vaccination was on Day 1]. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
GBS6 + Tdap	0 of 102 (0%)	81 of 102 (79.4%)	0 of 102
GBS6 + Placebo	0 of 99 (0%)	71 of 99 (71.7%)	0 of 99
Placebo + Tdap	1 of 103 (1%)	79 of 103 (76.7%)	0 of 103

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 24 May 2024.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 40036340Smith WB, Seger W, Chawana R, Skogeby Z, Silmon de Monerri NC, Feng Y, Gaylord M, Jongihlati B, Beeslaar J, Skinner JM, Bickham K, Anderson AS. A Phase 2b Trial Evaluating the Safety, Tolerability, and Immunogenicity of a 6-Valent Group B Streptococcus Vaccine Administered Concomitantly With Tetanus, Diphtheria, and Acellular Pertussis Vaccine in Healthy Nonpregnant Female Individuals. J Infect Dis. 2025 Jul 11;231(6):e1065-e1074. doi: 10.1093/infdis/jiaf096.
To obtain contact information for a study center near you, click here.Link provided by the sponsor.
Individual participant dataSharing planned: Yes. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Pfizer CT.gov Call Center study director

Pfizer

12 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 24 May 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 12 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 24 May 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of Participants Reporting Local Reactions Within 7 Days After Vaccination (time frame: Day 1 (day of vaccination) to Day 7). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04766086, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 May 2024.