Study of Mixed Vaccination Schedules With a 21-valent Pneumococcal Conjugate Vaccine and a 20-valent Pneumococcal Conjugate Vaccine in Healthy Infants From Approximately 2 Months of Age

Investigation of Different Vaccination Schedules in Infants

Recruiting
42 days - 89 days
All
Phase 3
580 participants needed
14 Locations

Study Overview

This study is a Phase 3, randomized, modified double-blind study which aims to measure whether the investigational pneumococcal conjugate vaccine PCV21 is safe and can help the body to develop germ-fighting agents called "antibodies" (immunogenicity) when it is given after 1 dose, 2 doses, or 3 doses of a licensed 20-valent pneumococcal vaccine compared to when 20-valent pneumococcal vaccine is given as a complete series in infants aged from approximately 2 months (42 to 89 days).

The study duration per participant will be up to approximately 19 months. The study vaccines (either PCV21 or 20vPCV) will be administered at approximately 2, 4, 6 and 12 to 15 months of age (MoA). Routine pediatric vaccines will be given as per local recommendations.

There will be 6 study visits:

Visit (V)01, V02 separated from V01 by 60 days, V03 separated from V02 by 60 days, V04 separated from V03 by 30 days, V05 at 12 months of age until 15 months of age, V06 separated from V05 by 30 days.

Eligibility Criteria

You may be eligible for this study if you meet the following criteria:

  • Conditions: Pneumococcal Immunization
  • Age: 42 days - 89 days
  • Gender: All

Inclusion Criteria:

  • Aged 42 to 89 days on the day of inclusion
  • Participants who are healthy as determined by medical evaluation including medical history and physical examination
  • Born at full term of pregnancy (≥ 37 weeks) and with a birth weight ≥ 2.5 kg or born after a gestation period above 28 (> 28 weeks) through 36 weeks with a birth weight ≥ 1.5 kg, and in both cases medically stable as assessed by the investigator

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

  • Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy
  • History of microbiologically confirmed Streptococcus pneumoniae infection or disease.
  • History of seizure or significant stable or progressive neurologic disorders such as inflammatory nervous system diseases, encephalopathy, cerebral palsy
  • Known systemic hypersensitivity to any of the study interventions components, or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances
  • Thrombocytopenia, or known thrombocytopenia, as reported by the parent/legal acceptable representative (LAR), contraindicating intramuscular (IM) injection.
  • Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection
  • Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion
  • Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
  • Previous vaccination against Streptococcus pneumoniae
  • Receipt of immune globulins, blood or blood-derived products since birth
  • Participation at the time of study enrollment (or in the 6 weeks preceding the first study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

This study investigates the safety and immune response of an investigational pneumococcal conjugate vaccine, referred to as PCV21, in infants. The purpose is to determine if PCV21 can stimulate the production of antibodies when administered after one, two, or three doses of a licensed 20-valent pneumococcal vaccine. This is compared to a complete series of the 20-valent pneumococcal vaccine alone. The study involves healthy infants starting from approximately 2 months of age.

Participants will receive either the investigational vaccine or the licensed vaccine at ages 2, 4, 6, and between 12 to 15 months. Routine pediatric vaccines will also be administered according to local guidelines. The study will involve multiple visits to monitor the infants' health and immune response to the vaccines.

  • Who can participate: Infants aged 42 to 89 days who are healthy and born at full term or after 28 weeks of gestation with specific birth weight criteria are eligible. Exclusion criteria include immunodeficiency, history of certain infections, and previous vaccination against Streptococcus pneumoniae.
  • Study details: Participants will receive either the investigational vaccine or the licensed vaccine at specified ages. The study will involve monitoring for immune response and health status. A placebo is not used in this study.
  • Study timelines and visits: The study will last approximately 19 months. The study requires 6 visits.
Updated on 10 Nov 2025. Study ID: NCT06824181

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