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Safety of PF-07872412 versus 20‑valent pneumococcal conjugate vaccine in healthy infants for prevention of pneumococcal disease

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study involves healthy infants and a vaccine that aims to protect against pneumococcal disease, an infection that can cause ear infections, pneumonia, and meningitis. The new product being tested is called the PG4 vaccine and it is compared with an already approved vaccine, Prevenar 20. Both vaccines are given by an intramuscular injection, which means the medicine is delivered into a muscle.

The purpose of the study is to describe the safety profile of the PG4 vaccine. Infants receive a single dose of either the study vaccine or the comparison vaccine and are then observed for a short time after the injection, followed by scheduled visits to check their health over the next weeks.

Researchers will watch for common side effects such as redness, swelling, pain at the injection site, fever, reduced appetite, irritability, or increased sleep. Any side effects, known as adverse events, and any serious side effects that require medical attention, called serious adverse events, will be recorded and reviewed.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit and enrollment

    You arrive at the study site and confirm your participation. the study staff will record your baseline health information.

    You will be assigned to receive either the test vaccine or the comparator vaccine.

  2. Step 2

    Vaccine administration

    A single dose of 0.5 ml of the assigned vaccine is given by intramuscular injection.

    The vaccine contains a mixture of pneumococcal polysaccharide antigens conjugated to crm197 and adsorbed on aluminium phosphate.

  3. Step 3

    Immediate observation

    After the injection you will be observed for a short period to check for any immediate reactions such as pain or swelling at the injection site.

  4. Step 4

    Follow‑up monitoring

    Throughout the study period you will be asked to report any local reactions (redness, swelling, pain) at the injection site.

    You will also report any systemic events such as fever, decreased appetite, irritability, or drowsiness/increased sleep.

    All adverse events and any serious adverse events will be recorded by the study team.

  5. Step 5

    Final assessment

    At the end of the study, which is expected to be on 2029‑01‑22, a final visit will be conducted to complete the safety assessment.

Who can join the trial?

5 criteria

  • The child must be a baby boy or girl who is about 2 months old, meaning between 42 and 98 days after birth (the day of birth counts as day 1).
  • The baby must be judged to be healthy by the doctor, based on the baby’s medical history and a physical check‑up (this is called a clinical assessment).
  • The parent or legal guardian must be willing and able to bring the baby to all study visits, follow the treatment plan, and do any other study tasks.
  • The baby must be expected to stay in the study for its whole length, and the parent or guardian must be reachable by phone during that time.
  • The parent or legal guardian must be able to sign an informed consent form, which means they agree to the study and understand the rules and restrictions, including those listed in the study’s written instructions.

Who cannot join the trial?

12 criteria

  • If you have ever had a severe adverse reaction to a vaccine, or a serious allergy such as anaphylaxis (a life‑threatening allergic reaction) to any part of the study vaccine or to vaccines that contain diphtheria toxoid, you cannot take part.
  • If you are taking or plan to take medicines that suppress the whole immune system (systemic immunosuppressants), such as chemotherapy drugs (cytotoxic agents) for cancer or autoimmune disease, you are excluded. This also includes having received or planning to receive blood, plasma, or immune‑globulin products (including hepatitis B immunoglobulin). Using skin creams that locally suppress immunity is allowed. If you have taken high‑dose steroid pills (systemic corticosteroids, e.g., prednisone) for at least 14 days within the month before the study, or plan to take them during the study, you cannot join. Inhaled or injected steroids for breathing or joint problems are permitted.
  • You cannot be using any investigational drugs, vaccines, or medical devices (experimental products that are not yet approved) from the start of the study until it ends.
  • If you are a child, grandchild, or other close family member (direct descendant) of the doctors, study staff, or company employees running the trial, you are not eligible.
  • If you have a major brain or nerve condition (neurological disorder), a history of seizures (including febrile seizures caused by fever), or serious conditions such as cerebral palsy, brain swelling (encephalopathy), fluid buildup in the brain (hydrocephalus), or serious problems related to being born early (like brain bleeding, breathing pauses needing extra oxygen, or severe lung disease), you cannot participate. Mild birth‑related injuries that are improving, such as Erb’s palsy, are allowed.
  • If you have a major birth defect (congenital malformation) or a serious long‑term illness (chronic disorder), you are excluded.
  • If you have ever had a confirmed serious infection caused by the bacteria Streptococcus pneumoniae (pneumococcal disease), you cannot join.
  • If you have a known or suspected weak immune system (immunodeficiency), such as low levels of immune proteins (immunoglobulin deficiencies), DiGeorge syndrome, widespread cancer (malignancy), leukemia, lymphoma, or have had an organ or bone‑marrow transplant, you are not eligible.
  • If you have a bleeding disorder that makes you bleed for a long time (bleeding diathesis) and a doctor believes an injection into the muscle (intramuscular injection) would be unsafe, you cannot participate.
  • If you were born without a spleen, have a spleen that does not work, or have had surgery to remove the spleen (asplenia), you are excluded.
  • If you have any other serious health problem or abnormal lab test result that a doctor thinks makes the study unsafe for you or could affect the study results, you cannot take part.
  • If you have already received, or plan to receive, any approved or experimental pneumococcal vaccine (vaccine against pneumonia bacteria) during the study, you are not eligible. Experimental vaccines given more than 14 days before or after the study vaccine are allowed.
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Investigated drugs

  • Prevenar 20

    is a pneumococcal conjugate vaccine that protects against 20 different types of the bacteria that cause pneumonia, meningitis, and ear infections. It is given as a small injection into the muscle (intramuscular) and contains purified sugar fragments (polysaccharides) from each bacterial type that are linked to a protein called CRM197 and attached to an aluminum phosphate adjuvant to help the immune system respond. In this study, Prevenar 20 is used as the standard vaccine (comparator) to compare the safety and tolerability of the new vaccine being tested.

  • PF-07872412

    is an experimental multivalent pneumococcal conjugate vaccine being evaluated in the trial. Like the comparator, it includes polysaccharide fragments from 20 pneumococcal serotypes that are conjugated to CRM197 and adsorbed on aluminum phosphate, but it also contains several additional components (identified by codes such as PF‑07338018, PF‑07872419, etc.) that are part of the new formulation. It is administered by intramuscular injection and is being studied to see if it is safe and well‑tolerated in healthy infants compared with the approved Prevenar 20 vaccine.

What is already known about the treatment

  • Prevenar 20 suspension for injection in pre-filled syringe Pneumococcal polysaccharide conjugate vaccine (20-valent, adsorbed)

    This vaccine is a clear liquid suspension that is given as a 0.5 ml intramuscular injection using a pre‑filled syringe. It is an approved and widely used product that protects against pneumococcal infections in infants and young children. The vaccine contains polysaccharide pieces from 20 different pneumococcal serotypes linked to a harmless protein (CRM197) and held on an aluminum phosphate base, which teaches the immune system to make protective antibodies. It belongs to the class of pneumococcal polysaccharide‑protein conjugate vaccines.

  • PF-07872412

    This investigational vaccine is also a 0.5 ml suspension for intramuscular injection. It is currently being studied in a phase 3 trial and is not yet approved for general use. Like the comparator, it includes the same 20 pneumococcal polysaccharides attached to CRM197 and adsorbed on aluminum phosphate, together with additional PF‑coded components that aim to boost the immune response, helping the body develop antibodies against pneumococcal disease. It is classified as an experimental pneumococcal conjugate vaccine.

Investigated diseases

Invasive pneumococcal disease - Invasive pneumococcal disease is caused by the bacteria Streptococcus pneumoniae. It often begins when the bacteria move from the nose or throat into normally sterile sites such as the blood, lungs, or brain. When it reaches the lungs it causes pneumonia, with cough, fever and difficulty breathing. If it spreads to the bloodstream it leads to bacteremia, which can cause fever and chills. In the brain it can cause meningitis, resulting in headache, stiff neck and altered consciousness. The infection can spread rapidly, moving from a localized site to multiple organs.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase IIITrial ID2025-523447-35-02Protocol codeC4931007Estimated enrolment2 400 patientsSponsorPfizer Inc.

sourced from the EU Clinical Trials Register and site verification

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