A Study to Learn About How a New Pneumococcal Vaccine Works in Infants

April 23, 2026 updated by: Pfizer

A Phase 2, Randomized, Double-Blind Trial to Evaluate the Safety, Tolerability, and Immunogenicity of a Multivalent Pneumococcal Conjugate Vaccine in Healthy Infants

The purpose of this study is to learn about the safety of a new pneumococcal vaccine and how the new pneumococcal vaccine helps to fight against germs in infants when compared to the pneumococcal vaccines that are currently in use, 20vPnC (Prevnar 20®) or another licensed pneumococcal vaccine.

To ensure that the new vaccine (PG4) stays stable, it is placed in a liquid mixture of sterile water and other substances (a solution). This study will also test if there is a difference in the safety and immune effects of the new pneumococcal vaccine when it is one type of solution compared to when it is in a different type of solution.

The immune response is how the body's cells; tissues and organs work together to protect the body from infection. Blood samples will be used to measure the amount of antibodies produced after the vaccination. Antibodies are proteins that protect you when an unwanted germ enters the body. This will help understand how well the new pneumococcal vaccine works. This vaccine can possibly provide protection against pneumococcal disease. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae.

This study is seeking participants who are:

  • male or female infants who are 2 months of age,
  • infants born at 36 weeks (about 8 and a half months) of pregnancy or later; and,
  • said to be healthy by the study doctor

There are four groups in this study. All participants will be assigned to one of the four groups. All study vaccines will be given as a single shot into the left thigh muscle. Participants in the three groups will have 3 blood samples collected during the 1 and a half years they are in the study.

The first 400 participants who enter the study will be assigned to either Group 1 or Group 2. Half the participants in Group 1 and half the participants in Group 2 will receive 4 doses at 2, 4, 6, and 12 to 15 months of age of PG4 mixed in the first solution. The other half of the participants in Groups 1 and 2 will receive 4 doses of 20vPnC (Prevnar 20®) at 2, 4, 6, and 12 to 15 months of age. The main difference between Groups 1 and 2 is that participants in Group 2 will have the first blood sample collected at an earlier time than those in Group 1.

Once 400 participants have been assigned to Groups 1 and 2 then 100 new participants will be assigned to Group 3. Half the participants in Group 3 will receive PG4 in the second solution at 2, 4, 6, and 12 to 15 months of age. The other half of the participants in Groups 3 will receive 4 doses of 20vPnC (Prevnar 20®) at 2, 4, 6, and 12 to 15 months of age.

Once the 100 participants have been assigned to Group 3 then 300 new participants will be assigned to Group 4. Half the participants in Group 4 will receive PG4 in the first solution at 2, 4, 6, and 12 to 15 months of age. The other half of the participants in Group 4 will receive 4 doses of a licensed pneumococcal comparator vaccine at 2, 4, 6, and 12 to 15 months of age.

Participants will take part in this study for about 16 to 19 months (about 1 and a half years). During this time, participants will have 6 study clinic visits and 1 to 2 phone calls. At these study clinic visits, parent(s) or legal guardian(s) will be asked if the participant experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

605

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Puerto Rico
      • Guayama, Puerto Rico, 00784
        • Clinical Research Puerto Rico
      • Ponce, Puerto Rico, 00716
        • Ponce Medical School Foundation Inc.
      • San Juan, Puerto Rico, 00907-1509
        • BRCR Global Puerto Rico
      • San Juan, Puerto Rico, 00935-6528
        • University of Puerto Rico - Medical Sciences Campus
      • San Juan, Puerto Rico, 00935
        • The Hispanic Alliance for Clinical and Translational Research
      • San Juan, Puerto Rico, 00918
        • CMRC Headlands, LLC
    • PR
      • Trujillo Alto, PR, Puerto Rico, 00976
        • San Miguel Medical
  • United States
    • Arkansas
      • Fayetteville, Arkansas, United States, 72703
        • Northwest Arkansas Pediatric Clinic
      • Jonesboro, Arkansas, United States, 72401
        • The Children's Clinic
    • California
      • La Puente, California, United States, 91744
        • Los Ninos Children's Medical Clinic
      • West Covina, California, United States, 91790
        • Los Ninos Children's Medical Clinic
    • District of Columbia
      • Washington D.C., District of Columbia, United States, 20016
        • Velocity Clinical Research, Washington DC
    • Florida
      • Miami Lakes, Florida, United States, 33014
        • Riveldi Biomedical Research and Associates - Miami
    • Idaho
      • Idaho Falls, Idaho, United States, 83404
        • Clinical Research Prime
    • Iowa
      • Ankeny, Iowa, United States, 50023
        • The Iowa Clinic
    • Kansas
      • Topeka, Kansas, United States, 66604
        • Cotton O'Neil Pediatrics
    • Kentucky
      • Bardstown, Kentucky, United States, 40004
        • Kentucky Pediatric/ Adult Research
      • Louisville, Kentucky, United States, 40291
        • Bluegrass Clinical Research, Inc.
      • Louisville, Kentucky, United States, 40243
        • All Children Pediatrics
    • Louisiana
      • Shreveport, Louisiana, United States, 71103
        • Louisiana State University Health Sciences Shreveport
      • Shreveport, Louisiana, United States, 71103
        • Ochsner/LSU Health Ambulatory Care Center
      • Shreveport, Louisiana, United States, 71101
        • LSUHSC Clinical Trials Office
    • Maryland
      • Baltimore, Maryland, United States, 21201
        • University of Maryland
      • Frederick, Maryland, United States, 21702
        • UMB/CVD
    • Massachusetts
      • Fall River, Massachusetts, United States, 02721
        • Pediatric Associates of Fall River
    • Montana
      • Great Falls, Montana, United States, 59405
        • Boeson Research GTF
      • Great Falls, Montana, United States, 59405
        • OBGYN Associates
      • Kalispell, Montana, United States, 59901
        • Heart and Hands Midwifery and Family Practice
      • Kalispell, Montana, United States, 59901
        • POEM Healthcare
      • Missoula, Montana, United States, 59804
        • Boeson Research MSO
      • Missoula, Montana, United States, 59804
        • Boeson Research KAL
      • Missoula, Montana, United States, 59804
        • Boeson Research Laboratory
    • Nebraska
      • Lincoln, Nebraska, United States, 68522
        • Midwest Children's Health Research Institute
    • New York
      • East Syracuse, New York, United States, 13057
        • Child Health Care Associates
      • Rochester, New York, United States, 14642
        • University of Rochester Medical Center
      • Rochester, New York, United States, 14611
        • University of Rochester
    • North Carolina
      • Durham, North Carolina, United States, 27703
        • Duke Vaccine and Trials Unit
      • Durham, North Carolina, United States, 27704
        • Durham Pediatrics at North Duke Street
      • Durham, North Carolina, United States, 27701
        • Velocity Clinical Research Inc.
      • Winston-Salem, North Carolina, United States, 27101
        • Javara Inc a Delaware corporation
    • Ohio
      • Dayton, Ohio, United States, 45409
        • Dayton Clinical Research
      • Dayton, Ohio, United States, 45414
        • Ohio Pediatric Research Assn.
      • South Euclid, Ohio, United States, 44121
        • Senders Pediatrics
    • Oregon
      • Gresham, Oregon, United States, 97030
        • Cyn3rgy Research
    • Pennsylvania
      • Erie, Pennsylvania, United States, 16506
        • Allegheny Health and Wellness Pavilion
      • Erie, Pennsylvania, United States, 16506
        • Square-1 Clincal Research
    • South Carolina
      • Summerville, South Carolina, United States, 29486
        • Coastal Pediatric Research
    • Tennessee
      • Kingsport, Tennessee, United States, 37660
        • Holston Medical Group
    • Texas
      • Dallas, Texas, United States, 75252
        • Oak Cliff Research Company, LLC
      • Dallas, Texas, United States, 75230
        • Javara - Privia Medical Group North Texas - Dallas
      • Dallas, Texas, United States, 75208
        • Oak Cliff Research Company, LLC
      • Edinburg, Texas, United States, 78539
        • PAS Research - McAllen
      • Houston, Texas, United States, 77087
        • Mercury Clinical Research - Pediatric Associates
      • Houston, Texas, United States, 77054
        • Mercury clinical research Inc.
      • League City, Texas, United States, 77573
        • University of Texas Medical Branch
      • Longview, Texas, United States, 75605
        • DCOL Center for Clinical Research
    • Utah
      • Kaysville, Utah, United States, 84037
        • Tanner Clinic - Kaysville
      • Kaysville, Utah, United States, 84037
        • AMR Clinical
      • Layton, Utah, United States, 84041
        • Tanner Clinic
      • Layton, Utah, United States, 84041
        • Tanner Memorial Clinic
      • Layton, Utah, United States, 84041
        • Alliance for Multispecialty Research, LLC
      • Murray, Utah, United States, 84107
        • AMR Clinical
      • Provo, Utah, United States, 84604
        • AMR Clinical
      • Roy, Utah, United States, 84067
        • AMR Clinical
      • South Jordan, Utah, United States, 84095
        • AMR Clinical
      • Syracuse, Utah, United States, 84075
        • AMR Clinical
    • Virginia
      • Charlottesville, Virginia, United States, 22902
        • Pediatric Research of Charlottesville, LLC

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male or female infants born at >36 weeks of gestation and 2 months of age at the time of consent.
  • Healthy infants determined by clinical assessment, including medical history and clinical judgment, to be eligible for the study.

Exclusion Criteria:

  • History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis).
  • Major known congenital malformation or serious chronic disorder.
  • Other acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study.
  • Previous vaccination with any licensed or investigational pneumococcal vaccine, or planned receipt through study participation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group 1 PG4
Multivalent Pneumococcal Vaccine
Biological: PG4
Multivalent pneumococcal conjugate vaccine
Active Comparator: Group 1 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine (20vPnC)
Biological: 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine
Other Names:
  • Prevnar 20
Experimental: Group 2 PG4
Multivalent Pneumococcal Vaccine
Biological: PG4
Multivalent pneumococcal conjugate vaccine
Active Comparator: Group 2 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine (20vPnC)
Biological: 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine
Other Names:
  • Prevnar 20
Experimental: Group 3 PG4
Multivalent Pneumococcal Vaccine
Biological: PG4
Multivalent pneumococcal conjugate vaccine
Active Comparator: Group 3 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine (20vPnC)
Biological: 20-valent pneumococcal conjugate vaccine (20vPnC)
20-valent pneumococcal conjugate vaccine
Other Names:
  • Prevnar 20
Experimental: Group 4 PG4
Multivalent Pneumococcal Vaccine
Biological: PG4
Multivalent pneumococcal conjugate vaccine
Active Comparator: Group 4 15-valent pneumococcal conjugate vaccine (PCV15)
15-valent pneumococcal conjugate vaccine (PCV15)
Biological: 15-valent pneumococcal conjugate vaccine (PCV15)
15-valent pneumococcal conjugate vaccine
Other Names:
  • PCV15

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of participants reporting local reactions within 7 days after each dose
Time Frame: Day 7
Prompted local reactions after each dose
Day 7
Percentage of participants reporting systemic events within 7 days after each dose
Time Frame: Day 7
Prompted systemic reactions after each dose
Day 7
Percentage of participants reporting adverse events (AEs)
Time Frame: Dose 1 to 1 month after Dose 3
AEs occurring from Dose 1 to 1 month after Dose 2
Dose 1 to 1 month after Dose 3
Percentage of participants reporting AEs
Time Frame: Dose 4 to 1 month after Dose 4
AEs occurring from Dose 4 to 1 month after Dose 4
Dose 4 to 1 month after Dose 4
Percentage of participants reporting serious adverse events (SAEs)
Time Frame: Dose 1 to 6 months after Dose 4
SAEs occurring from Dose 1 to 6 months after Dose 4
Dose 1 to 6 months after Dose 4

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pneumococcal immunoglobulin G (IgG) geometric mean concentrations (GMCs)
Time Frame: 1 month after Dose 4
Pneumococcal IgG GMCs 1 month after Dose 4
1 month after Dose 4

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Pfizer

Investigators

  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 25, 2024

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

July 23, 2024

First Submitted That Met QC Criteria

July 23, 2024

First Posted (Actual)

July 29, 2024

Study Record Updates

Last Update Posted (Actual)

April 28, 2026

Last Update Submitted That Met QC Criteria

April 23, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • C4931002
  • NCT06524414 (Registry Identifier: ClinicalTrials.gov)
  • 2025-000081-28 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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