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Testing a new pneumococcal vaccine in healthy infants

A Phase 3, Randomized, Modified Double-blind, Active-controlled, Parallel-group, 2-arm Study to Investigate the Safety and Immunogenicity of a 4-dose Regimen of a 21-valent Pneumococcal Conjugate Vaccine in Healthy Infants and Toddlers

PHASE3 · Sanofi · NCT06736041

This study is testing a new pneumococcal vaccine for healthy infants to see if it works better than the current vaccine in protecting them from infections.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment1630 (estimated)
Ages42 Days to 89 Days
SexAll
SponsorSanofi (industry)
Drugs / interventionschemotherapy, radiation
Locations70 sites (Tucson, Arizona and 69 other locations)
Trial IDNCT06736041 on ClinicalTrials.gov

What this trial studies

This Phase 3 clinical trial evaluates the safety and immunogenicity of a 21-valent pneumococcal conjugate vaccine (PCV21) compared to the licensed 20-valent pneumococcal vaccine (Prevnar 20) in healthy infants aged 2 to 15 months. Participants will receive either vaccine alongside routine pediatric vaccinations at specified intervals over approximately 19 months. The study involves six visits to monitor the infants' health and antibody development against pneumococcal infections.

Who should consider this trial

Good fit: Ideal candidates are healthy infants aged 42 to 89 days who meet specific birth weight and gestational age criteria.

Not a fit: Patients with known immunodeficiencies or a history of pneumococcal infections may not benefit from this study.

Why it matters

Potential benefit: If successful, this vaccine could enhance protection against pneumococcal diseases in infants.

How similar studies have performed: Previous studies of pneumococcal vaccines have shown success, indicating potential for this new approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
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
* Any contraindication to the routine pediatric vaccines being administered in the study
* History of seizure or significant stable or progressive neurological disorders such as infantile spasms, 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
* Laboratory-confirmed or known thrombocytopenia, as reported by the parent/legally 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.
* Receipt of any vaccine in the 4 weeks preceding the study intervention administration or planned receipt of any vaccine in the 4 weeks following the study intervention administration, except for US licensed influenza vaccination, which may be received at least 2 weeks before or 2 weeks after any study vaccination. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines, as applicable per local recommendations.
* Previous vaccination against S. pneumoniae
* Previous vaccination against the following antigens: diphtheria, tetanus, pertussis, Haemophilus influenzae type b, and poliovirus
* Receipt of more than 1 dose of hepatitis B vaccine
* 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.

Where this trial is running

Tucson, Arizona and 69 other locations

+20 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Pneumococcal Immunization

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.