Study to Learn About Safety, Tolerability, and Immune Response of a Catch-up Pneumococcal Vaccine in Children and Adolescents

August 27, 2026 updated by: Pfizer

A PHASE 3, RANDOMIZED DOUBLE-BLIND TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A CATCH-UP VACCINATION REGIMEN OF A MULTIVALENT PNEUMOCOCCAL CONJUGATE VACCINE IN HEALTHY CHILDREN AND ADOLESCENTS

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 that can cause pneumonia (lung infections), meningitis (brain infections), and otitis media (ear infections) in children when compared to the pneumococcal vaccine that is currently in use, 20vPnC (Prevnar 20®).

This study will test if the new pneumococcal vaccine is as safe as the one that is currently in use. It will also assess how the new vaccine works in comparison to the one that is currently in use. To measure how the new pneumococcal vaccine compares to the current one, blood samples will be used to measure the body's ability to create proteins to fight those germs. This new vaccine can possibly provide additional protection against germs that cause pneumococcal disease that are not included in the vaccines that are currently given to children. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae

This study is seeking participants who:

  • Are children aged 15 months to 18 years.
  • May or may not have received any doses of pneumococcal conjugate vaccine (PCV) in the past.

The study will be conducted in the United States, Puerto Rico, and other countries.

Participants will be assigned to 1 of 3 groups based on age:

Group 1: 15 months to less than 2 years (about 300 participants) Group 2: 2 years to less than 5 years (about 300 participants) Group 3: 5 years to less than 18 years (about 600 participants)

Within each group, participants will be assigned by chance in a 2:1 ratio to receive 1 vaccine injection (shot) with either PG4 (new vaccine) or 20vPnC, given in the arm or thigh. This means that for every 3 participants, about 2 will receive PG4 and about 1 will receive 20vPnC.

Each participant will take part in the study for approximately 6 months. During this time, each participant will visit a clinic 2 times (visit 1 for vaccination and visit 2 to follow up) and will be contacted via telephone once (for a 6 month follow up).

At the study clinic visits, participants will have their blood drawn and be asked if they have experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine. During the 6-month follow-up contact, participants will be asked about any further side effects.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

1200

Phase

  • Phase 3

Contacts and Locations

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

Study Contact

Study Locations

  • Puerto Rico
      • Caguas, Puerto Rico, 00725
        • Recruiting
        • Caguas Clinical Research LLC
      • Ponce, Puerto Rico, 00716
        • Recruiting
        • Ponce Medical School Foundation Inc. / CAIMED Center
      • San Juan, Puerto Rico, 00907-1509
        • Recruiting
        • BRCR Global Puerto Rico
      • San Juan, Puerto Rico, 00918
        • Recruiting
        • CMRC Headlands, LLC
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • Recruiting
        • UAB Child Health Research Unit (CHRU)
      • Birmingham, Alabama, United States, 35205
        • Recruiting
        • Alabama Clinical Therapeutics, LLC Birmingham Pediatric Associates
      • Guntersville, Alabama, United States, 35976
        • Recruiting
        • Lakeview Clinical Research, LLC
    • California
      • Fair Oaks, California, United States, 95628
        • Recruiting
        • Apex Research Group
      • Ontario, California, United States, 91762
        • Recruiting
        • Orange County Research Institute
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Recruiting
        • Children's Hospital Colorado
    • Florida
      • Miami Lakes, Florida, United States, 33016
        • Recruiting
        • Indago Research & Health Center, Inc
      • Miami Lakes, Florida, United States, 33014
        • Recruiting
        • Riveldi and Associates
      • Tampa, Florida, United States, 33617
        • Not yet recruiting
        • Children's Health Center
    • Idaho
      • Ammon, Idaho, United States, 83406
        • Recruiting
        • Medical Research Partners
      • Blackfoot, Idaho, United States, 83221
        • Recruiting
        • Bingham Memorial Hospital
      • Boise, Idaho, United States, 83702
        • Recruiting
        • ASR, LLC
    • Kentucky
      • Bardstown, Kentucky, United States, 40004
        • Recruiting
        • Kentucky Pediatric/ Adult Research
    • Louisiana
      • Covington, Louisiana, United States, 70433
        • Recruiting
        • Avacare
      • Lafayette, Louisiana, United States, 70508
        • Recruiting
        • Velocity Clinical Research, Lafayette
      • Shreveport, Louisiana, United States, 71101
        • Recruiting
        • LSU Health Shreveport Clinical Trials Office
      • Shreveport, Louisiana, United States, 71101
        • Recruiting
        • Ochsner/LSU Health Shreveport - Progressive Pediatrics
      • Shreveport, Louisiana, United States, 71103
        • Recruiting
        • Ochsner LSU Health Shreveport Ambulatory Care Center
      • Shreveport, Louisiana, United States, 71103
        • Recruiting
        • Ochsner/LSU Health Shreveport Academic Medical Center
    • Massachusetts
      • Fall River, Massachusetts, United States, 02721
        • Recruiting
        • Pediatric Associates of Fall River
    • Michigan
      • Bingham Farms, Michigan, United States, 48025
        • Recruiting
        • Michigan Center of Medical Research
    • Minnesota
      • Minneapolis, Minnesota, United States, 55402
        • Recruiting
        • Clinical Research Institute, Inc.
    • Nebraska
      • Lincoln, Nebraska, United States, 68504
        • Recruiting
        • Midwest Children's Health Research Institute
      • Lincoln, Nebraska, United States, 68505
        • Recruiting
        • Midwest Children's Health Research Institute
      • Lincoln, Nebraska, United States, 68516
        • Recruiting
        • Midwest Children's Health Research Institute
      • Lincoln, Nebraska, United States, 68522
        • Recruiting
        • Midwest Children's Health Research Institute
    • New York
      • East Syracuse, New York, United States, 13057
        • Recruiting
        • Child Health Care Associates
      • Horseheads, New York, United States, 14845
        • Recruiting
        • Corning Center for Clinical Research
      • Rochester, New York, United States, 14642
        • Recruiting
        • University of Rochester Medical Center
    • Ohio
      • Cincinnati, Ohio, United States, 45245
        • Recruiting
        • Pediatric Associates of Mt. Carmel
      • Cincinnati, Ohio, United States, 45206
        • Recruiting
        • Cincinnati Children's Hospital Medical Center Investigational Drug Services
      • Cincinnati, Ohio, United States, 45206
        • Recruiting
        • Cincinnati Children's Hospital Medical Center Vaccine Research Center
      • Dayton, Ohio, United States, 45409
        • Recruiting
        • Dayton Clinical Research
      • South Euclid, Ohio, United States, 44121
        • Recruiting
        • Senders Pediatrics
    • South Carolina
      • Simpsonville, South Carolina, United States, 29681
        • Recruiting
        • Tribe Clinical Research LLC. at Parkside Pediatrics Five Forks
    • Tennessee
      • Tullahoma, Tennessee, United States, 37388
        • Recruiting
        • Pediatric Clinical Trials of Tennessee, LLC
    • Texas
      • Corpus Christi, Texas, United States, 78411
        • Recruiting
        • Driscoll Children's Hosptial
      • Houston, Texas, United States, 77065
        • Recruiting
        • Kool Kids Pediatrics
      • Houston, Texas, United States, 77054
        • Recruiting
        • Mercury Clinical Research (Administrative Office)
      • Houston, Texas, United States, 77077
        • Recruiting
        • Mercury Clinical Research - Sunrise Pediatrics
      • Houston, Texas, United States, 77402
        • Recruiting
        • Neutra Life Sciences
      • Houston, Texas, United States, 77054
        • Recruiting
        • Mercury Clinical Research - Administrative Office
      • Houston, Texas, United States, 77074
        • Not yet recruiting
        • RTX Clinical Research
      • Houston, Texas, United States, 77087
        • Recruiting
        • Mercury Clinical Research - MD Kids Pediatrics
      • League City, Texas, United States, 77573
        • Recruiting
        • University of Texas Medical Branch,
      • Lewisville, Texas, United States, 75067
        • Not yet recruiting
        • Prime Clinical Research Inc.
      • Mansfield, Texas, United States, 76063
        • Not yet recruiting
        • Prime Clinical Research Inc.
      • Richmond, Texas, United States, 77469
        • Recruiting
        • Pediatric Center- Neutra Life Sciences
      • San Antonio, Texas, United States, 78215
        • Recruiting
        • Sun Research Institute
      • Victoria, Texas, United States, 77901
        • Recruiting
        • Victoria Clinical Research Group
    • Utah
      • Layton, Utah, United States, 84041
        • Recruiting
        • Tanner Clinic
      • Layton, Utah, United States, 84041
        • Recruiting
        • Tanner Clinic - Layton Parkway
      • Provo, Utah, United States, 84604
        • Recruiting
        • AMR Clinical
      • Syracuse, Utah, United States, 84075
        • Recruiting
        • AMR Clinical
      • West Jordan, Utah, United States, 84088
        • Recruiting
        • Velocity Clinical Research, Salt Lake City
    • Virginia
      • Charlottesville, Virginia, United States, 22902
        • Recruiting
        • Pediatric Research of Charlottesville, LLC
      • Richmond, Virginia, United States, 23226
        • Recruiting
        • Clinical Research Partners, 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:

Cohort 1 (Participants ≥15 Months to <2 Years of Age) Healthy toddlers and children ≥15 months to <2 years of age with documentation of prior receipt of PCV.

Cohort 2 (Participants ≥2 Years to <5 Years of Age) Healthy toddlers and children ≥2 years to <5 years of age with documentation of prior receipt of PCV if applicable.

Cohort 3 (Participants ≥5 Years to <18 Years of Age) Healthy children ≥5 years to <18 years of age with documentation of prior receipt of PCV (if applicable). A negative urine pregnancy test is required for individuals of childbearing potential (IOCBP). IOCBP or participants able to father must also agree to use a highly effective method of birth control.

Exclusion Criteria:

All Cohorts (Participants ≥15 Months to <18 Years of Age)

Children with significant medical, psychiatric, or neurological conditions (eg, immunodeficiency or history of seizure); or a history of confirmed invasive pneumococcal infection in the past will be excluded from enrolment in the trial

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: Triple

Arms and Interventions

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Percentage of Participants With Local Reactions Within 7 Days After Vaccination
Time Frame: Within 7 days after Vaccination
Within 7 days after Vaccination
Percentage of Participants With Systemic Events Within 7 Days after Vaccination
Time Frame: Within 7 days after Vaccination
Within 7 days after Vaccination
Percentage of Participants With Adverse Events (AEs)
Time Frame: From Vaccination to 1 month after Vaccination
From Vaccination to 1 month after Vaccination
Percentage of Participants With Serious Adverse Events (SAEs)
Time Frame: From Vaccination to 6 months after Vaccination
From Vaccination to 6 months after Vaccination
GMCs of serotype-specific IgG concentrations
Time Frame: 1 month after vaccination
1 month after vaccination
GMTs of serotype-specific OPA titers
Time Frame: 1 month after vaccination
1 month after vaccination

Secondary Outcome Measures

Outcome Measure
Time Frame
Percentage of participants with predefined serotype-specific IgG concentrations
Time Frame: 1 month after vaccination
1 month after vaccination
IgG GMFRs
Time Frame: 1 month after vaccination
1 month after vaccination
Percentage of participants with a ≥4-fold rise in serotype-specific OPA titers
Time Frame: before to 1 month after vaccination
before to 1 month after vaccination
OPA GMFRs
Time Frame: before to 1 month after vaccination
before to 1 month after vaccination

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)

June 15, 2026

Primary Completion (Estimated)

December 2, 2027

Study Completion (Estimated)

December 2, 2027

Study Registration Dates

First Submitted

June 15, 2026

First Submitted That Met QC Criteria

June 15, 2026

First Posted (Actual)

June 22, 2026

Study Record Updates

Last Update Posted (Actual)

August 31, 2026

Last Update Submitted That Met QC Criteria

August 27, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • C4931004
  • 2025 (U.S. NIH Grant/Contract: Faculty of Social Sciences Scientific Grant at the University of Gdańsk)
  • 2025-523445-10-00 (Registry Identifier: CTIS (EU))

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

product manufactured in and exported from the U.S.

Yes

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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