NCT07839871 · Pfizer
Study to Learn About a Respiratory Syncytial Virus Vaccine in Children at High Risk of RSV Disease
What this study is about
The purpose of the study is to evaluate the safety, tolerability, and immunogenicity of RSVpreF in children 5 to \<18 years of age at high risk for RSV disease, including those who are immunocompromised.
View original scientific description
The purpose of the study is to evaluate the safety, tolerability, and immunogenicity of RSVpreF in children 5 to \<18 years of age at high risk for RSV disease, including those who are immunocompromised.
Interventions
BIOLOGICAL
RSVpreF
RSVpreF Vaccine
BIOLOGICAL
Placebo
Placebo
Primary outcome measures
Cohort 1: Proportion of participants reporting pre-specified local reactions within 7 days following investigational product administration
Time frame: Within 7 days
Describe pre-specified local reactions in children 5 to \<18 years of age with chronic medical conditions
Cohort 2: Proportion of participants reporting pre-specified local reactions within 7 days following each investigational product administration
Time frame: Within 7 days
Describe pre-specified local reactions in children 5 to \<18 years of age with immunocompromising conditions
Cohort 1: Proportion of participants reporting pre-specified systemic events within 7 days following investigational product administration
Time frame: Within 7 days
Describe pre-specified systemic events in children 5 to \<18 years of age with chronic medical conditions
Cohort 2: Proportion of participants reporting pre-specified systemic events within 7 days following each investigational product administration
Time frame: Within 7 days
Describe pre-specified systemic events in children 5 to \<18 years of age with immunocompromising conditions
Cohort 1: Proportion of participants reporting adverse events (AEs) through 1 month following investigational product administration
Time frame: From vaccination through 1 month after vaccination
Describe AEs in children 5 to \<18 years of age with chronic medical conditions
Cohort 2: Proportion of participants reporting adverse events (AEs) through 1 month following last investigational product administration
Time frame: From vaccination through 1 month after last vaccination
Describe AEs in children 5 to \<18 years of age with immunocompromising conditions
Cohort 1: Proportion of participants reporting serious adverse events (SAEs) throughout the study
Time frame: From vaccination through 24 months after vaccination
Describe SAEs in children 5 to \<18 years of age with chronic medical conditions
Cohort 2: Proportion of participants reporting serious adverse events (SAEs) throughout the study
Time frame: From vaccination through 12 months after last vaccination
Describe SAEs in children 5 to \<18 years of age with immunocompromising conditions
Cohort 1: Proportion of participants reporting newly diagnosed chronic medical conditions (NDCMCs) throughout the study
Time frame: From vaccination through 24 months after vaccination
Describe NDCMCs in children 5 to \<18 years of age with chronic medical conditions
Cohort 2: Proportion of participants reporting newly diagnosed chronic medical conditions (NDCMCs) throughout the study
Time frame: From vaccination through 12 months after last vaccination
Describe NDCMCs in children 5 to \<18 years of age with immunocompromising conditions
Cohort 1: Geometric mean ratio (GMR), estimated by the ratio of the geometric mean titers (GMTs) for RSV A and RSV B serum neutralizing titers (NTs) 1 month after vaccination in participants in Study C3671017 Cohort 1 compared to those in Study C3671013
Time frame: 1 month after vaccination
Demonstrate that the immune responses elicited by RSVpreF in children 5 to \<18 years of age with chronic medical conditions are noninferior to the immune responses in adults ≥60 years of age
Cohort 1: Seroresponse rate of RSV A and RSV B serum NTs at 1 month after vaccination
Time frame: 1 month after vaccination
Demonstrate that the immune responses elicited by RSVpreF in children 5 to \<18 years of age with chronic medical conditions are noninferior to the immune responses in adults ≥60 years of age. Seroresponse is defined as a postvaccination NT ≥4 times the lower limit of quantitation (LLOQ) if the prevaccination titer is below the LLOQ; or a ≥4-fold rise from prevaccination if the prevaccination titer is ≥ LLOQ
Cohort 2: Neutralizing Titers (NTs) for RSV A and RSV B expressed as Geometric Mean Titers (GMT)
Time frame: Before each vaccination, 1 month after each vaccination, 12 months after last vaccination
Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions
Cohort 2: NTs for RSV A and RSV B expressed as Geometric Mean Fold Rise (GMFR)
Time frame: 1 month after each vaccination, 12 months after last vaccination
Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions
Cohort 2: NTs for RSV A and RSV B expressed as seroresponse rate
Time frame: 1 month after each vaccination, 12 months after last vaccination
Describe the immune responses elicited by 1 or 2 doses of RSVpreF in children 5 to \<18 years of age with immunocompromising conditions
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Participants' age requirements for each study cohort at enrollment, respectively Cohort 1a (chronic medical conditions) 12 to \<18 years of age Cohort 1b (chronic medical conditions) 5 to \<12 years of age Cohort 2a (immunocompromising conditions) 12 to \<18 years of age Cohort 2b (immunocompromising conditions) 5 to \<12 years of age
- Participants depending on the study cohort requirements, will be considered by the investigator to be at high risk of LRTI-RSV based on the following disease characteristics and definitions: Chronic medical conditions:
- Cystic fibrosis
- Medically treated asthma
- Other chronic respiratory diseases and malformations of the lung
- Trisomy 21 (Down syndrome)
- Neuromuscular disease
- Cerebral palsy
- Hemodynamically significant or symptomatic congenital heart disease
- Sickle cell disease
- Confirmed stable HIV disease defined as documented viral load \<50 copies/mL and CD4 count \>200 cells/mm3 within 6 months before enrollment, and on stable antiretroviral therapy for at least 6 months Immunocompromising conditions:
- Immunomodulatory therapy: Is on an active immunosuppressive (including cytotoxic) or immunomodulatory therapy at a stable dose. Patients taking steroids as monotherapy must be on a dose of at least 2 mg/kg/day or 20 mg/day or greater OR
- Primary immune deficiency: Has a diagnosed primary immunodeficiency disease OR
- Cellular therapy: Has received a bone marrow or stem cell transplant at least 6 months (180 days) prior to enrollment with adequate immune reconstitution for immunization in the investigator's opinion or has received chimeric antigen receptor T cell (CAR-T) therapy more than 90 days prior to enrollment OR
- Solid organ transplant: Has received a solid organ transplant at least 3 months prior and with no acute rejection episodes within 90 days prior to enrollment and is on ongoing immunosuppressive therapy OR
- End-stage renal disease: Has end-stage renal disease (ESRD) on hemodialysis (HD)
- Participants' weight must be: Cohort 1a: ≥30.0 kg at enrollment Cohort 1b: ≥14.5 kg at enrollment Cohort 2a : ≥30 kg at enrollment Cohort 2b: ≥14.5 kg at enrollment •The participant's parent(s)/legal guardian is capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in the protocol. Depending on the age of the participant and according to local requirements, participants will also be asked to provide assent as appropriate (verbal or written) Key
Exclusion criteria
- Applicable to Cohort 1 (a and b) participants only: Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination
- Applicable to Cohort 1 (a and b) participants only: Individuals with a history of autoimmune disease, past or present, requiring therapeutic intervention including, but not limited to, systemic lupus erythematosus. Note: Stable type 1 diabetes and hypothyroidism are permitted
- History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s)
- Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection
- Individuals with epilepsy or other seizure disorders that is uncontrolled/unstable, or a history of seizures and/or other neurological complications following vaccination
- History of Guillain-Barré syndrome and/or acute polyneuropathy without an underlying etiology.
- Individuals who are pregnant
- Any medical or psychiatric condition, including any active suicidal ideation in the past year or suicidal behavior in the past 5 years or laboratory abnormality, that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study
Where
- Durham, North Carolina
- Cincinnati, Ohio
- South Euclid, Ohio
- Seattle, Washington
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Nov 6, 2026 · Source of record for eligibility and locations