NCT07794748 · Pfizer
A Study to Assess the Safety, Tolerability, and Immunogenicity of 3 Lots of a Multivalent Pneumococcal Conjugate Vaccine Administered to Adults
What this study is about
The purpose of this study is to provide safety data and demonstrate lot consistency with the PG4 vaccine by evaluating the immunogenicity of 3 different lots of this vaccine. This study will compare a new pneumococcal vaccine with the vaccine currently in use to see if they are similarly safe. It will also compare three batches of the new vaccine to make sure they work the same way.
View original scientific description
The purpose of this study is to provide safety data and demonstrate lot consistency with the PG4 vaccine by evaluating the immunogenicity of 3 different lots of this vaccine. This study will compare a new pneumococcal vaccine with the vaccine currently in use to see if they are similarly safe. It will also compare three batches of the new vaccine to make sure they work the same way. Blood samples will be taken to measure how the body responds to the vaccines. The study will be conducted in the United States. Participants will be assigned to 1 of 4 groups. Group 1: PG4 vaccine lot 1; Group 2: PG4 vaccine lot 2; Group 3: PG4 vaccine lot 3; Group 4: 20vPnC. Within each group, participants will be assigned by chance in a 2:2:2:1 ratio to receive 1 vaccine injection (shot) with either PG4 (new vaccine) lot 1, PG4 lot 2, PG4 Lot 3 or 20vPnC, given in the arm. This means that for every 7 participants, about 2 will receive either PG4 lot 1, lot 2 or lot 3 and about 1 will receive 20vPnC. Each participant will take part in the study for approximately 6 months.
Interventions
BIOLOGICAL
PG4 Multivalent Vaccine
Multivalent Pneumococcal Vaccine
BIOLOGICAL
PG4 Multivalent Vaccine
Multivalent Pneumococcal Vaccine
BIOLOGICAL
PG4 Multivalent Vaccine
Multivalent Pneumococcal Vaccine
BIOLOGICAL
20 Valent Pneumococcal Conjugate Vaccine (20vPnC)
20 Valent Pneumococcal Conjugate Vaccine
Primary outcome measures
Percentage of Participants with Prespecified Local Reactions Within 7 Days After Vaccination
Time frame: Within 7 days after Vaccination
Prompted local reactions after each dose
Percentage of Participants reporting Prespecified Systemic Events Within 7 Days after Vaccination
Time frame: Within 7 days after Vaccination
Prompted systemic events after each dose
Percentage of Participants with Adverse Events (AEs)
Time frame: From Vaccination to 1 month after Vaccination
AEs occurring from Dose 1 to 1 month after the vaccination
Percentage of Participants with Serious Adverse Events (SAEs)
Time frame: From Vaccination to 6 months after Vaccination
SAEs occurring from Dose 1 to 6 months after the vaccination
OPA geometric mean ratios (GMR) between each pair of PG4 vaccine lots
Time frame: 1 month after Vaccination
OPA GMRs between each pair of PG4 vaccine lots at 1 month after vaccination
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
- Adults 18 through 49 years of age, who have no history of receiving a pneumococcal vaccine after 5 years of age.
Exclusion criteria
- Individuals with a history of severe allergic reactions to a vaccine or its components, serious chronic medical disorders, significant psychiatric conditions, known or suspected immunodeficiency, substance abuse issues, asplenia, bleeding diathesis or prolonged bleeding, a history of a prior confirmed invasive pneumococcal infection, and pregnant or breastfeeding females will be excluded from enrollment in the trial.
Where
- Birmingham, Alabama
- Lake Forest, California
- Walnut Creek, California
- Milford, Connecticut
- Doral, Florida
- Hollywood, Florida
- Jacksonville, Florida
- Miami, Florida
- Miami Lakes, Florida
- Palmetto Bay, Florida
- West Palm Beach, Florida
- Fayetteville, Georgia
And 19 more locations — see the full list below.
Related conditions & keywords
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 Sep 23, 2026 · Source of record for eligibility and locations