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A Study to Assess the Safety, Tolerability, and Immunogenicity of 3 Lots of a Multivalent Pneumococcal Conjugate Vaccine Administered to Adults
A PHASE 3, RANDOMIZED, DOUBLE-BLIND TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF 3 LOTS OF A MULTIVALENT PNEUMOCOCCAL CONJUGATE VACCINE IN ADULTS
Who can join
Ages 18 to 49 · All sexes · Healthy volunteers welcome
Full eligibility criteria
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.
About the study
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.
What is being tested
- PG4 Multivalent Vaccine (biological)
- PG4 Multivalent Vaccine (biological)
- PG4 Multivalent Vaccine (biological)
- 20 Valent Pneumococcal Conjugate Vaccine (20vPnC) (biological)
Sponsor: Pfizer · Participants: 4,670 · Started: Sep 8, 2026
Contact the study team
- Pfizer CT.gov Call Center · Phone: 1-800-718-1021
Official record on ClinicalTrials.gov — NCT07794748
Locations in the U.S.
Conditions
From ClinicalTrials.gov, data retrieved Sep 30, 2026. Each study sets its own eligibility; the study team decides who can join.