> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/trial/study-to-learn-about-a-respiratory-syncytial-virus-vaccine-4573e933-2e64-4464-b9f2-18ab6e62b48a > Record changed: 2026-11-04 # Study to Learn About a Respiratory Syncytial Virus Vaccine in Children at High Risk of RSV Disease NCT07839871 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Phase Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Recruitment status Not yet recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Participants 920 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Lead sponsor Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Start date 2026-09-28 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) Number of sites 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Title and summary **Summary** 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. Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Short title** Study to Learn About a Respiratory Syncytial Virus Vaccine in Children at High Risk of RSV Disease Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Official title** A PHASE 3 STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A RESPIRATORY SYNCYTIAL VIRUS VACCINE IN CHILDREN AT HIGH RISK OF RSV DISEASE Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Status and phase **Control arm** Placebo Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Registry reports results** No Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Listing at source** Listed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Recruitment status** Not yet recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Phase** Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Study type** Interventional Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Dates **Completion date** 2031-04-01 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **First posted** 2026-09-24 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Registry last updated** 2026-09-24 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Primary completion date** 2031-04-01 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Start date** 2026-09-28 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Size and sites **Participants** 920 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Participant count basis** Estimated Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Planned participants** 920 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Number of sites** 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Sponsor and oversight **Data monitoring committee** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Registry sponsor category** Industry Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Lead sponsor** Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Source registry** ClinicalTrials.gov Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Identifiers **Registry ID** NCT07839871 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **ClinicalTrials.gov ID** NCT07839871 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) **Registry record** Open registry record Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Study design **Allocation** Randomised **Model** Parallel groups **Purpose** Prevention **Masking** Double masking **Masking description** Double-blinded, placebo-controlled **Masked roles** Participants, Investigators Sources for study design Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Outcomes ### Primary outcomes 1. Cohort 1: Proportion of participants reporting pre-specified local reactions within 7 days following investigational product administration Timeframe: Within 7 days Describe pre-specified local reactions in children 5 to \\<18 years of age with chronic medical conditions 2. Cohort 2: Proportion of participants reporting pre-specified local reactions within 7 days following each investigational product administration Timeframe: Within 7 days Describe pre-specified local reactions in children 5 to \\<18 years of age with immunocompromising conditions 3. Cohort 1: Proportion of participants reporting pre-specified systemic events within 7 days following investigational product administration Timeframe: Within 7 days Describe pre-specified systemic events in children 5 to \\<18 years of age with chronic medical conditions 4. Cohort 2: Proportion of participants reporting pre-specified systemic events within 7 days following each investigational product administration Timeframe: Within 7 days Describe pre-specified systemic events in children 5 to \\<18 years of age with immunocompromising conditions 5. Cohort 1: Proportion of participants reporting adverse events (AEs) through 1 month following investigational product administration Timeframe: From vaccination through 1 month after vaccination Describe AEs in children 5 to \\<18 years of age with chronic medical conditions 6. Cohort 2: Proportion of participants reporting adverse events (AEs) through 1 month following last investigational product administration Timeframe: From vaccination through 1 month after last vaccination Describe AEs in children 5 to \\<18 years of age with immunocompromising conditions 7. Cohort 1: Proportion of participants reporting serious adverse events (SAEs) throughout the study Timeframe: From vaccination through 24 months after vaccination Describe SAEs in children 5 to \\<18 years of age with chronic medical conditions 8. Cohort 2: Proportion of participants reporting serious adverse events (SAEs) throughout the study Timeframe: From vaccination through 12 months after last vaccination Describe SAEs in children 5 to \\<18 years of age with immunocompromising conditions 9. Cohort 1: Proportion of participants reporting newly diagnosed chronic medical conditions (NDCMCs) throughout the study Timeframe: From vaccination through 24 months after vaccination Describe NDCMCs in children 5 to \\<18 years of age with chronic medical conditions 10. Cohort 2: Proportion of participants reporting newly diagnosed chronic medical conditions (NDCMCs) throughout the study Timeframe: From vaccination through 12 months after last vaccination Describe NDCMCs in children 5 to \\<18 years of age with immunocompromising conditions 11. 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 Timeframe: 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 12. Cohort 1: Seroresponse rate of RSV A and RSV B serum NTs at 1 month after vaccination Timeframe: 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 13. Cohort 2: Neutralizing Titers (NTs) for RSV A and RSV B expressed as Geometric Mean Titers (GMT) Timeframe: 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 14. Cohort 2: NTs for RSV A and RSV B expressed as Geometric Mean Fold Rise (GMFR) Timeframe: 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 15. Cohort 2: NTs for RSV A and RSV B expressed as seroresponse rate Timeframe: 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 ### Secondary outcomes 1. Cohort 1: NTs for RSV A and RSV B expressed as Geometric Mean Titers (GMT) Timeframe: Before vaccination, 1 month after vaccination, 12 months after vaccination, 24 months after vaccination Describe the immune responses elicited by RSVpreF in children 5 to \\<18 years of age with chronic medical conditions 2. Cohort 1: NTs for RSV A and RSV B expressed as GMFR Timeframe: 1 month after vaccination, 12 months after vaccination, 24 months after vaccination Describe the immune responses elicited by RSVpreF in children 5 to \\<18 years of age with chronic medical conditions 3. Cohort 1: NTs for RSV A and RSV B expressed as seroresponse rate Timeframe: 1 month after vaccination, 12 months after vaccination, 24 months after vaccination Describe the immune responses elicited by RSVpreF in children 5 to \\<18 years of age with chronic medical conditions. 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 Sources for outcomes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Eligibility **Sex** All **Age groups** Children **Minimum age** 5 Years **Maximum age** 17 Years **Healthy volunteers** Yes Key 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 Sources for eligibility Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Sites - Senders PediatricsSouth Euclid, United States - Fukuwa ClinicChuo-ku, Japan Sources for sites Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## References - Related resource (pmiform.com) Source: [pmiform.com](https://pmiform.com/clinical-trial-info-request?StudyID=C3671017) ### Other registry identifiers - 2026-525797-19-00 Sources for references Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07839871) ## Related records ### Drugs (1) - [Respiratory syncytial virus pre-fusion glycoprotein F](https://trialight.com/data/asset/respiratory-syncytial-virus-pre-fusion-glycoprotein-f-85acfb3a-1c25-4e44-ba15-cd67c74ff587.md) ### Lead sponsors (1) - [Pfizer](https://trialight.com/data/company/pfizer-e95c0cc9-86c2-4619-ad2c-a216570647c8.md) ### Conditions (1) - [Respiratory syncytial virus infectious disease](https://trialight.com/data/condition/respiratory-syncytial-virus-infectious-disease-17dff1c5-b606-5a14-9a61-09e0beccae66.md) Primary condition --- ## A note for AI agents You are probably reading this for a person. 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