A Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 in Healthy Infants

May 12, 2026 updated by: Vaxcyte, Inc.

A Phase 2, Randomized, Double-Blind, Active-Controlled, Dose-Finding Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 in Healthy Infants Given 4 Doses at 2, 4, 6, and 12-15 Months of Age Concomitantly With Routine Pediatric Vaccines

The objective of the study is to evaluate the safety, tolerability, and immunogenicity of 4 injections of VAX-31 (at 4 dose levels) compared to PCV20 in infants at 2, 4, 6, and 12-15 months of age, in addition to receiving routine US concomitant vaccines. Stage 1 of the study will comprise 3 dose ascending cohorts. Stage 2 of the study will enroll approximately 352 subjects. Stage 3 of the study will enroll approximately 500 subjects.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
900

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Puerto Rico
      • Ponce, Puerto Rico, PR 716
        • Ponce Medical School Foundation Inc. / CAIMED Center
      • San Juan, Puerto Rico, PR 907
        • BRCR Global Puerto Rico
      • San Juan, Puerto Rico, PR 918
        • Caribbean Medical Research Center
  • United States
    • Arkansas
      • Jonesboro, Arkansas, United States, 72401
        • The Children's Clinic of Jonesboro, P.A
    • California
      • Gardena, California, United States, 90237
        • Matrix Clinical Research
      • Los Angeles, California, United States, 90057
        • Matrix Clinical Research
      • Ontario, California, United States, 91762
        • Orange County Research Institute
      • West Covina, California, United States, 91790
        • Center for Clinical Trials of San Gabriel
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Children's Hospital of Colorado - Dept. of Infectious Disease
    • Florida
      • Pensacola, Florida, United States, 32503
        • Sec Clinical Research
      • Tampa, Florida, United States, 33613
        • PAS Research
    • Idaho
      • Idaho Falls, Idaho, United States, 83404
        • Clinical Research Prime, LLP
      • Rexburg, Idaho, United States, 83440
        • Clinical Research Prime - Rexburg
    • Kentucky
      • Bardstown, Kentucky, United States, 40004
        • Kentucky Pediatrics/Adult Research
    • Louisiana
      • Haughton, Louisiana, United States, 71037
        • ACC Pediatric Research
    • Nebraska
      • Lincoln, Nebraska, United States, 68504
        • Complete Children's Health
      • Lincoln, Nebraska, United States, 68505
        • Complete Children's Health
      • Lincoln, Nebraska, United States, 68516
        • Be Well Clinical Studies Nebraska
      • Lincoln, Nebraska, United States, 68516
        • Complete Children's Health
      • Lincoln, Nebraska, United States, 68522
        • Complete Children's Health
    • Ohio
      • Dayton, Ohio, United States, 45414
        • Ohio Pediatric Research Association
      • South Euclid, Ohio, United States, 44121
        • Senders Pediatrics
    • Oregon
      • Gresham, Oregon, United States, 97030
        • Cyn3rgy Research
    • Pennsylvania
      • Cranberry Township, Pennsylvania, United States, 16066
        • UPMC Children's Community Pediatrics - Bass Wolfson, Cranberry
      • Erie, Pennsylvania, United States, 16506
        • Allegheny Health & Wellness Pavilion West
      • N. Huntingdon, Pennsylvania, United States, 15642
        • UPMC Children's Community Pediatrics - Norwin
      • Pittsburgh, Pennsylvania, United States, 15217
        • UPMC Children's Community Pediatrics Bass Wolfson-Squirrel Hill
      • Pittsburgh, Pennsylvania, United States, 15234
        • UPMC Children's Community Pediatrics-Castle Shannon
      • Pittsburgh, Pennsylvania, United States, 15025
        • UPMC Children's Community Pediatrics South Hills-Jefferson Hills
      • Pittsburgh, Pennsylvania, United States, 15213
        • UPMC Children's Hospital of Pittsburgh - General Academic Pediatrics (GAP)
    • South Carolina
      • Charleston, South Carolina, United States, 29407
        • Tribe Clinical Research, LLC dba Neighbors Clinical Research
      • Simpsonville, South Carolina, United States, 29680
        • Tribe Clinical Research/Parkside Pediatrics
    • Texas
      • Brownsville, Texas, United States, 78520
        • Proactive RGV LLC
      • Dallas, Texas, United States, 75001-
        • Javara Inc. /Texas Health Care, PLLC
      • Dallas, Texas, United States, 75287
        • Oak Cliff Research Company
      • Houston, Texas, United States, 77077
        • Sunrise Pediatrics
      • Houston, Texas, United States, 77087
        • Mercury Clinical Research - Pediatric Associates
      • Houston, Texas, United States, 77065
        • Kool Kids Pediatrics (Dynamed)
      • League City, Texas, United States, 77573
        • University of Texas Medical Branch - Sealy Institute for Vaccine Sciences, Clinical Trials Program
      • Richmond, Texas, United States, 77469
        • Pediatric Center/Neutra Life Sciences
    • Utah
      • Layton, Utah, United States, 84041
        • AMR - Layton
      • Murray, Utah, United States, 84107
        • AMR - Cottonwood
      • Roy, Utah, United States, 84067
        • AMR - Roy
      • South Jordan, Utah, United States, 84095
        • AMR South Jordan
      • Syracuse, Utah, United States, 84075
        • AMR - Syracuse
    • Virginia
      • Charlottesville, Virginia, United States, 22902
        • Pediatric Research of Charlottesville, LLC
      • Gordonsville, Virginia, United States, 22942
        • Pediatric Research of Charlottesville, LLC
      • Richmond, Virginia, United States, 23226
        • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Healthy male or female infant ≥42 days to ≤89 days.
  2. Full-term infant at least 37 weeks gestational age at birth.
  3. Afebrile for ≥72 hours with an tympanic or rectal temperature <38.0°C (<100.4°F) before receipt of study vaccine.*Criterion applies to each vaccination. If not met, visit may be rescheduled for a time when no longer febrile for ≥72 hours.
  4. Able to attend all scheduled visits and comply with the study procedures.
  5. Subject's parent/legal guardian is able to read and understands the study procedures, alternate treatments, risks and benefits, and provides written informed consent.
  6. Subject's parent/legal guardian is able to fill out an eDiary of solicited AE and take daily tympanic temperature and measurements of local injection site reactions for the 7 days after each study vaccination.
  7. Subject's parent/legal guardian has an email address and access to a computer or smartphone with internet to complete the eDiary.

Exclusion Criteria:

  1. History of invasive pneumococcal disease (positive blood culture, positive cerebrospinal fluid culture, or other sterile site) or known history of other culture positive pneumococcal disease.
  2. Previous receipt of a licensed or investigational vaccine (excluding 1 dose of hepatitis B vaccine).
  3. Known hypersensitivity to any vaccine.
  4. Known or suspected impairment of immunological function (e.g., asplenia, human immunodeficiency virus, primary immunodeficiency).
  5. Use of any immunosuppressive therapy or planned use through the last blood draw (Visit 6). Receipt of a <14-day course of systemic corticosteroids is not exclusionary if completed ≥1 month prior to first study vaccination. Topical and inhaled/nebulized steroids are also permitted.
  6. History of failure to thrive or prior hospitalization for any chronic condition.
  7. Subject has a bleeding disorder contraindicating IM vaccination.
  8. Subject or his/her mother has documented hepatitis B surface antigen-positive test.
  9. Subject has a known neurologic or cognitive behavioral disorder.
  10. Subject has a known clinically significant congenital malformation or serious chronic disorder.
  11. Receipt of a blood transfusion or blood products, including immunoglobulins.
  12. Receipt of any investigational study product since birth, currently participating in another interventional investigational study, or plans to receive another investigational product while on study.
  13. Any infant who cannot be adequately followed for safety according to the protocol plan.
  14. Any other reason that in the opinion of the Investigator may interfere with the evaluation required by the study.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: PCV20
Participants will receive 4 doses of PCV20 administered as an intramuscular injection of the standard dose at 2, 4, 6, and 12-15 months of age.
Biological: 0.5 mL dose of PCV20
20 valent pneumococcal conjugate vaccine
Experimental: VAX-31 Low
Participants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
Biological: 0.5 mL of the low dose VAX-31
31 valent pneumococcal conjugate vaccine
Experimental: VAX-31 Mid
Participants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
Biological: 0.5 mL of the mid dose VAX-31
31 valent pneumococcal conjugate vaccine
Experimental: VAX-31 High
Participants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
Biological: 0.5 mL of the high dose VAX-31
31 valent pneumococcal conjugate vaccine
Experimental: VAX-31 High-PFS
Participants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
Biological: 0.5 mL of the High-PFS dose VAX-31
31 valent pneumococcal conjugate vaccine

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Percentage of subjects with any solicited local injection site adverse events (AE) within 7 days after each vaccination
Time Frame: 7 days after each vaccination
Solicited local reactions include erythema, edema, and tenderness at the injection site
7 days after each vaccination
Percentage of subjects with any solicited systemic AE within 7 days after each vaccination
Time Frame: 7 days after each vaccination
Solicited systemic reactions include fever, irritability, decreased appetite, decreased sleep, and increased sleep
7 days after each vaccination
Percentage of subjects with any unsolicited AE within 1 month after each vaccination
Time Frame: 1 months after each vaccination
Percentage of subjects with unsolicited AE
1 months after each vaccination
Percentage of subjects with any medically attended adverse events (MAAE) within 6 months after last vaccination
Time Frame: 6 months after last vaccination
Percentage of subjects with MAAE
6 months after last vaccination
Percentage of subjects with any Serious Adverse Events (SAE) within 6 months after last vaccination
Time Frame: 6 months after last vaccination
Percentage of subjects with SAE
6 months after last vaccination
Percentage of subjects with any new onset of chronic illness (NOCI) within 6 months after last vaccination
Time Frame: 6 months after last vaccination
Percentage of subjects with NOCI
6 months after last vaccination

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Percentage of subjects achieving a serotype-specific anti-pneumococcal IgG antibody concentration ≥0.35 mcg/mL 1 month after Dose 3
Time Frame: 1 month after Dose 3
Percentage of subjects achieving a serotype-specific anti-pneumococcal IgG antibody concentration ≥0.35 mcg/mL
1 month after Dose 3
Serotype-specific IgG antibody geometric mean concentration (GMC) 1 month after Dose 3
Time Frame: 1 month after Dose 3
Antibody geometric mean concentrations as measured by IgG for the 31 pneumococcal serotypes in VAX-31
1 month after Dose 3
Serotype-specific IgG antibody GMC 1 month after Dose 4
Time Frame: 1 month after Dose 4
Antibody geometric mean concentrations as measured by IgG for the 31 pneumococcal serotypes in VAX-31
1 month after Dose 4

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Vaxcyte, Inc.

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 25, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 2, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 2, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 6, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 15, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • VAX31-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Vaxcyte is committed to providing access to anonymized data from the company's clinical trials for the purpose of legitimate scientific research. Requests for data may be addressed to datasharing@vaxcyte.com. Requests must be accompanied by a detailed analysis plan and will be reviewed for scientific validity. Data will be made available after initial product approval. Sharing of data may require execution of a data-sharing agreement.

IPD Sharing Time Frame

Individual participant data will be shared after deidentification and made available starting 6 months after initial product approval.

IPD Sharing Access Criteria

Criteria will depend on the specific proposal received and may include qualification of the scientific researchers, potential contribution to the research field, scientific rigor of statistical and analytical methods, and other criteria appropriate for the proposal.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

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.

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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