A Phase 3 interventional study of PG4 and 20-valent pneumococcal conjugate vaccine (20vPnC) in Pneumococcal Disease, sponsored by Pfizer. Recruiting at 77 sites in 4 countries. Open to participants aged 15 Months to 17 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-26.
Sponsored by Pfizer · Phase 3, Interventional, and Prevention
Among 60 studies in Pneumococcal Infections by Pfizer — 5 open to participants now, 8 under way, 5 of them phase 3. Pneumococcal Infections · Pfizer.
Among the 60 studies in Pneumococcal Infections by Pfizer, this one is the 17th largest by planned enrollment of the 49 interventional ones that give a count, is one of 5 that started in 2026, is one of 30 in phase 3, and was the 58th registered.
298 studies on the registry are indexed under Pneumococcal Infections; 26 are open to participants now.
Browse Pneumococcal Infections studies →5 of the 60 studies in Pneumococcal Infections by Pfizer are open now, in 12 countries. Recruiting first, the newest first:
Pfizer · Sites in United States
Pfizer · Sites in China
Pfizer · Sites in United States, Japan, Puerto Rico
Pfizer · Sites in United States, Argentina, Australia and 8 more countries
By country, each count listing its studies:
Of the 21 Pneumococcal Infections studies recruiting now, 4 (19%) set no upper age limit and 15 (71%) stop at 75 or younger; 14 take children under 18; 17 take healthy volunteers.
This study: 15 Months to 17 Years · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
60 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 8 · Phase 2 8 · Phase 3 30 · Phase 4 4
First in 2005; this study’s year is marked. 5 started in 2026.
This study's planned enrollment of 1,200 is above the median of 373 across 253 interventional studies indexed under Pneumococcal Infections.
Median enrollment 570 across the 49 interventional studies, 1,100 across the 11 observational. Of the 52 that completed or were terminated, 39 (75%) have results posted.
This tab as a report to print or save as PDF → With an account.
Pfizer is the lead sponsor of 3,334 studies on the registry; 149 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 391 (65%) have results posted.
4 of the studies in Pneumococcal Infections by Pfizer that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07794748Phase 3PfizerA Study to Assess the Safety, Tolerability, and Immunogenicity of 3 Lots of a Multivalent Pneumococcal Conjugate Vaccine Administered to Adults | 2027-06-07 |
| NCT06622109PfizerA Study to Learn About the Safety of PREVENAR 20 Vaccine in Infants Aged Between Two to Six Months | 2026-12-04 |
| NCT06524414PfizerA Study to Learn About How a New Pneumococcal Vaccine Works in Infants | 2027-03-04 |
| NCT07023081PfizerA Study to Understand the Safety of the 20vPnC Vaccine in Healthy Chinese Adults, Children, and Infant | 2027-06-10 |
Among the 60 studies in Pneumococcal Infections by Pfizer, from their registry updates:
This tab as a report to print or save as PDF → With an account.
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 children 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. 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 children. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae
This study is seeking participants who:
The study will be conducted in the United States, Puerto Rico, and other countries.
Participants will be assigned to 1 of 3 groups based on age:
Group 1: 15 months to less than 2 years (about 300 participants) Group 2: 2 years to less than 5 years (about 300 participants) Group 3: 5 years to less than 18 years (about 600 participants)
Within each group, participants will be assigned by chance in a 2:1 ratio to receive 1 vaccine injection (shot) with either PG4 (new vaccine) or 20vPnC, given in the arm or thigh. This means that for every 3 participants, about 2 will receive PG4 and about 1 will receive 20vPnC.
Each participant will take part in the study for approximately 6 months. During this time, each participant will visit a clinic 2 times (visit 1 for vaccination and visit 2 to follow up) and will be contacted via telephone once (for a 6 month follow up).
At the study clinic visits, participants will have their blood drawn and be asked if they have experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine. During the 6-month follow-up contact, participants will be asked about any further side effects.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Cohort 1 (Participants ≥15 Months to \<2 Years of Age) Healthy toddlers and children ≥15 months to \<2 years of age with documentation of prior receipt of PCV.
Cohort 2 (Participants ≥2 Years to \<5 Years of Age) Healthy toddlers and children ≥2 years to \<5 years of age with documentation of prior receipt of PCV if applicable.
Cohort 3 (Participants ≥5 Years to \<18 Years of Age) Healthy children ≥5 years to \<18 years of age with documentation of prior receipt of PCV (if applicable). A negative urine pregnancy test is required for individuals of (IOCBP). IOCBP or participants able to father must also agree to use a highly effective method of .
Exclusion Criteria:
All Cohorts (Participants ≥15 Months to \<18 Years of Age)
Children with significant medical, psychiatric, or neurological conditions (eg, immunodeficiency or history of seizure); or a history of confirmed invasive pneumococcal infection in the past will be excluded from enrolment in the trial
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Multivalent Pneumococcal vaccine
Biological: PG4
20-valent pneumococcal conjugate vaccine (20vPnC)
Biological: 20-valent pneumococcal conjugate vaccine (20vPnC)
Multivalent Pneumococcal Vaccine
20-valent pneumococcal conjugate vaccine (20vPnC)
Also known as: Prevnar 20
Percentage of Participants With Local Reactions Within 7 Days After Vaccination
Time frame: Within 7 days after Vaccination
Percentage of Participants With Systemic Events Within 7 Days after Vaccination
Time frame: Within 7 days after Vaccination
Percentage of Participants With Adverse Events (AEs)
Time frame: From Vaccination to 1 month after Vaccination
Percentage of Participants With Serious Adverse Events (SAEs)
Time frame: From Vaccination to 6 months after Vaccination
GMCs of serotype-specific IgG concentrations
Time frame: 1 month after vaccination
GMTs of serotype-specific OPA titers
Time frame: 1 month after vaccination
Percentage of participants with predefined serotype-specific IgG concentrations
Time frame: 1 month after vaccination
IgG GMFRs
Time frame: 1 month after vaccination
Percentage of participants with a ≥4-fold rise in serotype-specific OPA titers
Time frame: before to 1 month after vaccination
OPA GMFRs
Time frame: before to 1 month after vaccination
Plan to share: Yes — Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Data sharing details ↗ · www.pfizer.com
Started Jun 2026 (actual). Primary completion is estimated for Dec 2027, 17 months after the start.
Of 81 industry-sponsored phase 3 interventional studies under Pneumococcal Infections, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 23. This study's planned 17 months is above that.
Counting every sponsor, half of 82 studies reached it within 13 months; a quarter within 9 and three quarters within 23.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.