A Phase 3 interventional study of PCV21 vaccine and Prevnar 20 vaccine in Pneumococcal Immunization, sponsored by Sanofi Pasteur, a Sanofi Company. Active, not recruiting at 112 sites in 6 countries. Open to participants aged 42 Days to 89 Days, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-22.
Sponsored by Sanofi Pasteur, a Sanofi Company (part of Sanofi) · Phase 3, Interventional, and Prevention
This study is a Phase 3, randomized, modified double-blind study which aims to measure whether PCV21 vaccine (investigational pneumococcal conjugate vaccine) is safe and can help the body to develop germ-fighting agents called "antibodies" (immunogenicity) compared with 20-valent pneumococcal vaccine (Prevnar 20, licensed pneumococcal conjugate vaccine) when they are administered with routine pediatric vaccines 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 20-valent pneumococcal vaccines) will be administered at approximately 2, 4, 6 and 12 to 15 months of age. Routine pediatric vaccines will be given at the same timepoints.
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.
Sanofi Pasteur, a Sanofi Company is the lead sponsor of 374 studies on the registry; 4 are open to participants now.
Of its 94 completed or terminated interventional studies of FDA-regulated products, 73 (78%) have results posted.
First submitted after Sanofi Pasteur became part of Sanofi.
Counted across the registry records on this site, refreshed daily.
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.
Exclusion Criteria:
Participants are excluded from the study if any of the following criteria apply:
Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical 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.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will be administered via intramuscular injection (IM) a 3-dose primary series of PCV21 at approximately 2, 4 and 6 months of age (MoA) co- administered with Vaxelis or Hexaxim (for participants included in South Korea only) and RotaTeq. At toddler age (12 to 15 MoA), a 4th dose of PCV21 will be administered concomitantly with a single dose of M-M-M-R II and Varivax.
Biological: PCV21 vaccine · Biological: M-M-R II vaccine · Biological: RotaTeq · Biological: Vaxelis vaccine · Biological: Varivax · Biological: Hexaxim Vaccine
Participants will be administered via intramuscular injection (IM) a 3-dose primary series of 20vPCV at approximately 2, 4 and 6 months of age (MoA) co- administered with Vaxelis or Hexaxim (for participants included in South Korea only) and RotaTeq. At toddler age (12 to 15 MoA), a 4th dose of 20vPCV will be administered concomitantly with a single dose of M-M-M-R II and Varivax.
Biological: Prevnar 20 vaccine · Biological: M-M-R II vaccine · Biological: RotaTeq · Biological: Vaxelis vaccine · Biological: Varivax · Biological: Hexaxim Vaccine
Pharmaceutical form:Suspension for injection-Route of administration:Intramuscular
Also known as: 515
Pharmaceutical form:Suspension for injection-Route of administration:Intramuscular
Also known as: Prevnar20®
Pharmaceutical form:Powder, lyophilized, for suspension for reconstitution-Route of administration:Subcutaneous or Intramuscular
Also known as: M-M-R® II
Pharmaceutical form:Solution-Route of administration:Oral
Also known as: RotaTeq®
Pharmaceutical form:Suspension for injection-Route of administration:Intramuscular
Also known as: Vaxelis®
Pharmaceutical form:Powder, lyophilized, for suspension for reconstitution-Route of administration:Subcutaneous or Intramuscular
Also known as: Varivax®
Pharmaceutical form:Suspension for injection-Route of administration:Intramuscular
Also known as: Hexaxim®
Seroresponse rate for PCV21 serotypes
Serotype specific IgG concentration ≥ 0.35 µg/mL
Time frame: 30 days post-dose 3
IgG concentration for PCV21 serotypes
Serotype specific IgG Geometric Mean Concentration (GMC)
Time frame: 30 days post-dose 3
IgG concentration for PCV21 serotypes
Serotype specific IgG GMC post-dose 4
Time frame: 30 days post-dose 4
Anti- hepatitis B surface antigen (HBsAg) Ab
% Antibody concentrations ≥ 10 milli international units per milliliter (mIU/mL)
Time frame: 30 days post-dose 3
Anti- polyribosylribitol phosphate (PRP) Ab
% Antibody concentrations ≥ 0.15 micrograms per milliliter (µg/mL)
Time frame: 30 days post-dose 3
Anti-poliovirus types (1, 2, and 3) Ab
% Antibody titers ≥ 1:8
Time frame: 30 days post-dose 3
Anti-diphtheria Ab concentrations
% Antibody concentrations ≥ 0.1 IU/mL
Time frame: 30 days post-dose 3
Anti-tetanus Ab concentrations
% Antibody concentrations ≥ 0.1 IU/mL
Time frame: 30 days post-dose 3
Anti-pertussis Ab concentrations (Pertussis toxin (PT) and Filamentous Hemagglutinin (FHA))
Antibody GMC
Time frame: 30 days post-dose 3
Anti-rotavirus serum immunoglobulin A (IgA) Ab concentrations
Antibody GMC
Time frame: 30 days post-dose 3
Anti-measles Ab concentrations
% Antibody concentrations ≥ 225 milli international units per milliliter (mIU/mL)
Time frame: 30 days post-dose 4
Anti-measles Ab concentrations
Antibody GMC
Time frame: 30 days post-dose 4
Anti-mumps Ab concentrations
% Anti-mumps Ab concentrations ≥ 10 Ab units (AbU)/mL
Time frame: 30 days post-dose 4
Anti-mumps Ab concentrations
Antibody GMC
Time frame: 30 days post-dose 4
Anti-rubella Ab concentrations
% Anti-rubella Ab concentrations ≥ 10 IU/mL
Time frame: 30 days post-dose 4
Anti-rubella Ab concentrations
Antibody GMC
Time frame: 30 days post-dose 4
Anti-varicella Ab concentrations
Anti-varicella Ab concentrations ≥ 5 glycoprotein enzyme linked immunosorbent assay (gpELISA) units/mL
Time frame: 30 days post-dose 4
IgG concentration for the additional serotype 9N
Serotype 9N specific IgG concentration ≥ 0.35 µg/mL
Time frame: 30 days post-dose 3
IgG concentration for serotype 3
Serotype 3 specific IgG concentration ≥ 0.35 µg/mL
Time frame: 30 days post-dose 3
IgG concentration for additional serotype 9N
Serotype 9N specific IgG GMC
Time frame: 30 days post-dose 3
IgG concentration for serotype 3
Serotype 3 specific IgG GMC
Time frame: 30 days post-dose 3
Serotype 9N specific IgG GMC post-dose 4
Serotype 9N specific IgG GMC post-dose 4
Time frame: 30 days post-dose 4
IgG concentration for additional serotype 9N
Serotype 9N specific IgG GMC post-dose 4
Time frame: 30 days post-dose 4
IgG concentration for serotype 3
Serotype 3 specific IgG GMC post-dose 4
Time frame: 30 days post-dose 4
Seroresponse rate for PCV21 serotypes
Serotype specific IgG concentration ≥ 0.35 µg/mL
Time frame: 30 days post-dose 4
IgG concentration for PCV21 serotypes
Serotype specific IgG GMC prior to and post-dose 4
Time frame: Before dose 4 and 30 days post-dose 4
Serotype specific OPA titers for all serotypes included in PCV21
Antibody GMC
Time frame: 30 days post-dose 3
Serotype specific OPA titers ≥ lower limit of quantitation (LLOQ) for all serotypes included in PCV21
Antibody GMC
Time frame: 30 days post-dose 3
Serotype specific OPA titers for all serotypes included in PCV21
Antibody GMC prior to and post-dose 4
Time frame: Before dose 4 and 30 days post-dose 4
Serotype specific OPA titers ≥ lower limit of quantitation (LLOQ) for all serotypes included in PCV21
Antibody GMC prior to and post-dose 4
Time frame: Before dose 4 and 30 days post-dose 4
Presence of any immediate adverse events (AEs)
Number of participants experiencing solicited and unsolicited immediate AEs
Time frame: Within 30 minutes after each vaccine injection
Presence of solicited injection site and systemic reactions through 7 days after each vaccine injection
Number of participants experiencing solicited injection site and systemic reactions
Time frame: Through 7 days after each vaccine injection
Presence of unsolicited (spontaneously reported) injection site reactions and unsolicited systemic AEs through 30 days after each vaccine injection
Number of participants experiencing unsolicited injection site reactions and unsolicited systemic AEs
Time frame: Through 30 days after each vaccine injection
Presence of serious adverse events (SAEs) throughout the study (through 6 months post- last vaccine injection)
Number of participants experiencing SAEs
Time frame: Throughout the study (through 6 months post-last vaccine injection), approximately 20 months
Showing the first 100 of 112 sites across 6 countries. Choose a country and city above to see the rest.
Plan to share: Yes — Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
This study is active, not recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Pneumococcal 21-Valent Conjugate Vaccine
Sanofi Pasteur, a Sanofi Company →