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Pneumococcal VaccinesPhase 3NCT07365826

A Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 With Influenza Vaccine in Adults ≥ 50 Years of Age

A Phase 3 study testing 31-valent pneumococcal conjugate vaccine and Seasonal Influenza Vaccine (SIV) (Flublok) in people with Pneumococcal Vaccines, run by Vaxcyte, Inc. at 25 sites in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

This is a Phase 3, randomized, double-blind study to evaluate the safety and immunogenicity of VAX-31 and seasonal influenza vaccine in pneumococcal-naïve adults ≥ 50 years when the two vaccines are administered at the same visit or separately. Read more about this study

Who is it for?
Ages 50 years and olderHealthy volunteers can take part
Conditions the study is for
Pneumococcal Vaccines
What is being tested?
31-valent pneumococcal conjugate vaccine and Seasonal Influenza Vaccine (SIV) (Flublok)
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
1,390 participants
Where
25 sitesUnited States
Study dates
12 Jan 2026to Mar 2027
Phase
Phase 3
Are there results?
Not yet: the study is under way

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 50 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Male or female ≥50 years of age (inclusive) at the time of randomization into the study.
  • Able and willing to complete the informed consent process.
  • Available for clinical follow-up through the last study visit at 7 months after the first study vaccination.
  • In good general health or with stable underlying chronic condition(s), as determined by medical history, oral temperature, physical examination, and clinical judgment of the Investigator.
  • Willing to have blood samples collected and used for research purposes.
  • Able to provide proof of identity to the satisfaction of the study site personnel completing the enrollment process.
  • Female subjects of childbearing potential, defined as premenopausal females capable of becoming pregnant, must have a negative urine pregnancy test at Screening and immediately prior to each vaccination and agree to use acceptable contraception, if heterosexually active. Female subjects who are not abstinent from heterosexual intercourse must agree to consistently practice contraception at least 7 days prior to vaccination and through their last study visit. Male subjects with partners of childbearing potential must agree to practice an acceptable contraception method ([use condoms with or without spermicide] or have undergone a vasectomy) from Day 1 through their last study visit. Note: A history of amenorrhea for at least 12 months without an alternative medical cause is required for a female to be considered postmenopausal in the study.
  • Able to access and use a device connected to Wi-Fi or cellular network for completion of an electronic diary (eDiary).

Who cannot join

  • History of IPD or pneumococcal pneumonia (either confirmed or self-reported) at any age.
  • Previous receipt of a licensed or investigational pneumococcal vaccine at any age.
  • Previous receipt of an influenza vaccine from the current season; receipt of any influenza vaccine (licensed or investigational) within 6 months prior to Day 1; or receipt/planned receipt of any licensed or investigational non-study influenza vaccine during study participation.
  • Receipt of any investigational product within 30 days prior to Day 1, currently participating in another interventional investigational study, or having plans to receive another investigational product(s) while on study.
  • Planned or actual administration of any licensed vaccine within 30 days prior to Day 1.
  • Body temperature >38.0°C (>100.4°F) or acute illness within 3 days prior to study vaccination (participant may be rescreened).
Show all 18Show fewer
  • Current diagnosis of human immunodeficiency virus (HIV), Hepatitis B, or Hepatitis C.
  • History of severe allergic reaction with generalized urticaria, angioedema, or anaphylaxis to any previous vaccination.
  • History of Guillain-Barré syndrome.
  • Individual who is pregnant, breastfeeding, or planning to become pregnant during study participation.
  • Has a known or suspected immunocompromising condition, including, but not limited to, leukemia, lymphoma, chronic renal failure, or congenital or acquired immunodeficiency.
  • Bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) resulting in clinically significant bruising or bleeding difficulties with IM injections or blood draws.
  • Receipt of blood or blood product (including polyclonal intravenous immunoglobulin) within 60 days prior to Day 1.
  • Receiving immunosuppressive therapy.
  • Received any part of a ≥14-day course of systemic corticosteroids (prednisone equivalent >10 mg/day) within 14 days of study vaccinations. Note: Receipt of a ≥14-day course of systemic corticosteroids equivalent to ≤10 mg/day is permitted, as are inhaled, nebulized, topical, intra-articular, and intrabursal corticosteroids.
  • History of malignancy ≤5 years before to Day 1, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
  • Any medical, psychiatric, or social condition that in the judgment of the Investigator is a contraindication to protocol participation or impairs a participant's ability to give informed consent.
  • Employee of, or first-degree relative of any person employed by the Sponsor, the contract research organization (CRO), the Investigator, study site personnel, or site.

Trial locations and contacts

25 sites in 1 country.

25 sites in 1 country

United States25 sites

  • Tekton Research at Austin

    Austin, Texas, 78745

  • REX Clinical Trials

    Beaumont, Texas, 77701

  • Charlottesville Medical Research Center

    Charlottesville, Virginia, 22911

  • CTI Clinical Research Center

    Cincinnati, Ohio, 45212

  • University Clinical Research - Deland

    DeLand, Florida, 32720-0834

  • Epic Medical Research

    DeSoto, Texas, 75115

  • DM Clinical Research - Detroit

    Detroit, Michigan, 48076

  • Tekton Research at Fort Collins

    Fort Collins, Colorado, 80525

  • DelRicht Research - Hendersonville

    Hendersonville, Tennessee, 37075

  • CenExel Research Centers of America

    Hollywood, Florida, 33024

  • Health Awareness

    Jupiter, Florida, 33458

  • AMR Knxoville

    Knoxville, Tennessee, 37909

  • Accel Research Sites - Lakeland

    Lakeland, Florida, 33803

  • Accel Research Sites - Largo

    Largo, Florida, 33777

  • Johnson County ClinTrials

    Lenexa, Kansas, 66219

  • AMR Lexington

    Lexington, Kentucky, 40509

  • Health Research of Hampton Roads, Inc.

    Newport News, Virginia, 23606

  • Coastal Carolina Research Center

    North Charleston, South Carolina, 29405

  • Velocity Omaha

    Omaha, Nebraska, 68134

  • Hope Research Institute

    Phoenix, Arizona, 85032

  • Clinical Research Partners, LLC.

    Richmond, Virginia, 23226

  • Rochester Clinical Research

    Rochester, New York, 14609

  • CenExel JBR Clinical Research

    Salt Lake City, Utah, 84107

  • Precision Clinical Research

    Sunrise, Florida, 33351

  • Velocity Valparaiso

    Valparaiso, Indiana, 46383

Other trials in United States

About this study

Official title: A Phase 3, Randomized, Double-Blind, Placebo-Controlled Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 Concomitantly Administered With Seasonal Influenza Vaccine in Healthy Subjects 50 Years of Age and Older

This is a Phase 3, randomized, double-blind study to evaluate the safety and immunogenicity of VAX-31 and seasonal influenza vaccine in pneumococcal-naïve adults ≥ 50 years when the two vaccines are administered at the same visit or separately.

Being tested
31-valent pneumococcal conjugate vaccine, Seasonal Influenza Vaccine (SIV) (Flublok), Placebo
Keywords
31-Valent PCV, Pneumonia, Pneumococcal Infection
Medical subject headings
Pneumonia, Pneumococcal Infections

What participants receive

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

  • 31-valent pneumococcal conjugate vaccineBiological

    0.5 mL of VAX-31 will be administered into the deltoid muscle

  • Seasonal Influenza Vaccine (SIV) (Flublok)Biological

    0.5 mL of SIV into the deltoid muscle

  • PlaceboBiological

    0.5mL of placebo (normal saline) into the deltoid muscle

Study groups in NCT07365826
Study groupRoleWhat they receive
VAX-31 + SIVExperimentalParticipants will receive a single dose of VAX-31 administered as an intramuscular injection at Day 1, concomitantly administered with SIV, followed by placebo at Month 1.
Receives: Biological: 31-valent pneumococcal conjugate vaccine; Biological: Seasonal Influenza Vaccine (SIV) (Flublok); Biological: Placebo
Placebo + SIVExperimentalParticipants will receive placebo administered via intramuscular injection at Day 1, concomitantly administered with SIV, followed by VAX-31 at Month 1.
Receives: Biological: 31-valent pneumococcal conjugate vaccine; Biological: Seasonal Influenza Vaccine (SIV) (Flublok); Biological: Placebo

What is being measured

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

  1. For each of the 32 serotypes (the 31 serotypes included in VAX-31, and serotype 20B), the ratio (co-administration group to sequential administration group) of opsonophagocytic activity (OPA) geometric mean titers (GMT) in evaluable participants

    Measured: 1 Month after VAX-31 vaccination

  2. For each of the strains in SIV, the ratio (co-administration group to sequential administration group) of hemagglutination inhibition (HAI) GMT in evaluable participants

    Measured: 1 Month after SIV administration

  3. Percentage of participants reporting solicited local adverse events (AE) within 7 days after Day 1 and Month 1 vaccination (redness, swelling, and pain at injection site) in each group

    Measured: 7 days after each vaccination

  4. Percentage of participants reporting solicited systemic AE within 7 days after Day 1 and Month 1 vaccination (fever, headache, fatigue, muscle pain, and joint pain) in each group

    Measured: 7 days after each vaccination

  5. Percentage of participants reporting unsolicited AE within 1 month after Day 1 and Month 1 vaccination in each group

    Measured: 7 days after each vaccination

  6. Percentage of participants reporting NOCI, MAAE, and SAE within 6 months after last vaccination in each group

    Measured: 6 Months after last vaccination

Secondary outcomes (1)

  1. For each of the 32 serotypes (the 31 serotypes included in VAX-31, and serotype 20B), the ratio (co-administration group to sequential administration group) of IgG geometric mean concentrations (GMC) in evaluable participants

    Measured: 1 month after VAX-31 administration

Timeline

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

  1. First posted26 Jan 2026
  2. Study start12 Jan 2026
  3. Primary completionMar 2027 (estimated)
  4. Study completionMar 2027 (estimated)

Resources

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 3
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
1,390 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07365826
Sponsor's protocol ID
VAX31-106
Status last verified
Jun 2026
First submitted
22 Jan 2026
Last updated
30 Jun 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: 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.

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing 31-valent pneumococcal conjugate vaccine and Seasonal Influenza Vaccine (SIV) (Flublok) in people with Pneumococcal Vaccines, run by Vaxcyte, Inc. at 25 sites in United States.

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 8 inclusion and 18 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: under way, not looking for participants, as of the sponsor's last update on 30 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 25 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

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

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

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?

For each of the 32 serotypes (the 31 serotypes included in VAX-31, and serotype 20B), the ratio (co-administration group to sequential administration group) of opsonophagocytic activity (OPA) geometric mean titers (GMT) in evaluable participants (time frame: 1 Month after VAX-31 vaccination). The study lists 6 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 NCT07365826.

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 30 Jun 2026.

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