NCT07629440 · Pfizer
A Study to Learn About How a New Pneumococcal Vaccine Works in Infants.
What this study is about
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 infants when compared to the pneumococcal vaccine that is currently in use, 20vPnC (Prevnar 20®).
View original scientific description
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 infants 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 when given with other childhood vaccines. 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 infants. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae. There are three groups in this study. All participants will be assigned to one of the three groups. This study is seeking participants who are: * infants who are 2 months of age in Group 1; * infants who are 2 to 6 months of age in Groups 2 and 3; and * said to be healthy by the study doctor About 3000 infants will be assigned to Group 1. The infants in this group will have a 1 in 2 chance (50%) of receiving either PG4 (new vaccine) or 20vPnC (currently in use) into the left thigh muscle at 2, 4, 6, and 12 to 15 months of age. About 140 infants from outside the United States will be assigned to Group 2. The infants in this group will have a 1 in 2 chance (50%) of receiving either PG4 or 20vPnC into the left thigh muscle at 2 to 6, 3 to 8, 4 to 10, and 12 to 15 months of age. About 90 infants from outside the United States will be assigned to Group 3. The infants in Group 3 will have a 1 in 3 chance (33%) of receiving either PG4 into the left thigh muscle, PG4 under the skin of the left thigh, or 20vPnC into the left thigh muscle at 2 to 6, 3 to 8, 4 to 10, and 12 to 15 months of age. Infants in Group 1 will take part in this study for about 16 to 19 months (about 1 and a half years). Infants in Groups 2 and 3 will take part in this study for 12 to 21 months (about 1 to 1 and a half years). During this time, infants will have 6 study clinic visits and 1 phone call. At these study clinic visits, parent(s)/legal guardian(s) will be asked if the infant experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine. Infants will have 3 blood samples collected.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- infants who are 2 months of age in Group 1.
- infants who are 2 to 6 months of age in Groups 2 and 3.
- 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.
Where
- Birmingham, Alabama
- Centreville, Alabama
- Fayetteville, Arkansas
- Jonesboro, Arkansas
- Sherwood, Arkansas
- Arcadia, California
- El Monte, California
- Fresno, California
- Montebello, California
- National City, California
- Palo Alto, California
- Aurora, Colorado
And 48 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 9, 2026 · Source of record for eligibility and locations