> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/trial/a-phase-iii-control-study-of-the-safety-and-immunogenicity-6385456c-101b-4bf6-9c7c-f19d7ecb00d7 > Record changed: 2026-10-13 # A Phase III Control Study of the Safety and Immunogenicity of vYF in Pediatric Population NCT07103148 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Phase Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Recruitment status Recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Participants 2,440 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Lead sponsor Sanofi Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Start date 2025-07-11 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) Number of sites 13 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Title and summary **Summary** The purpose of this study is to determine whether vYF (investigational vaccine) is safe and can help the body to develop antibodies (immunogenicity) compared with Stamaril vaccine and YF-VAX vaccine (both licensed vaccines) and when they are co-administered with Measles Mumps Rubella (MMR) vaccines in infants aged 11-15 months. Number of Participants: A total of 2440 participants is planned to be enrolled in VYF04 study. Study Arms and Duration: Eligible participants will be randomized in 2 independent groups (9-24 months, 2-5 years) to receive 1 dose of either vYF or Stamaril or YF-VAX in a 2:1:1 ratio within each age group. An additional group with participants of 11-15 months of age will also receive at the same vaccination visit vYF and a single dose of MMR vaccine. For the 2nd step (YF booster vaccine administration in a subset), at the Year (Y) 3 visit, a subset of 120 participants of the 9-24 months of age group who did receive a YF vaccine on Day(D) 01 will be invited to join a booster dose assessment (booster dose administered after the Y3 visit blood sample has been taken). Participants aged 11 to 15 months at the time of the concomitant administration of vYF and MMR will not be eligible for receiving a booster dose. The duration of each participation will be approximately 3 years for all participants (including participants co-administered on D01 with vYF and MMR), and 6 more months post-booster dose administration for the participants enrolled in the booster subset. Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Short title** A Phase III Control Study of the Safety and Immunogenicity of vYF in Pediatric Population Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Official title** A Parallel Group, Phase III Randomized, Modified Double-blind, Active Controlled Study to Investigate the Immunogenicity and Safety of vYF Compared to Licensed YF Vaccines in Pediatric Population Aged 9 Months to 5 Years of Age Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Status and phase **Control arm** Active comparator Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Registry reports results** No Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Listing at source** Listed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Recruitment status** Recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Phase** Phase 3 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Study type** Interventional Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Dates **Completion date** 2030-03-04 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **First posted** 2025-08-05 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Registry last updated** 2026-05-06 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Primary completion date** 2026-08-08 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Start date** 2025-07-11 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Size and sites **Participants** 2,440 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Participant count basis** Estimated Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Planned participants** 2,440 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Protocol amendments** 0 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Randomisation ratio** 2:1:1 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Number of sites** 13 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Sponsor and oversight **Data monitoring committee** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Registry sponsor category** Industry Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Lead sponsor** Sanofi Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Source registry** ClinicalTrials.gov Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Identifiers **Registry ID** NCT07103148 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **ClinicalTrials.gov ID** NCT07103148 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) **Registry record** Open registry record Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Study design **Allocation** Randomised **Model** Parallel groups **Purpose** Prevention **Masking** Quadruple masking **Masking description** \* Sponsor, Investigators, Study staff who conduct the safety assessment and the participant' parent(s) / LAR(s) will not know which study intervention is administered. \* Only the study staff who prepare and administer the study interventions and are not involved with the safety evaluation will know which study intervention is administered. **Masked roles** Participants, Care providers, Investigators, Outcome assessors Sources for study design Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Outcomes ### Primary outcomes 1. Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the Stamaril in YF-naive participants (9-24 months) Timeframe: At Day 29, 28 days post-vaccination (on Day 01) with vYF or Stamaril Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value 2. Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the YF-VAX in YF-naive participants (9-24 months) Timeframe: At Day 29, 28 days post-vaccination (on Day 01) with vYF or YF-VAX Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value 3. Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the Stamaril in YF-naive participants (2-5 years) Timeframe: At Day 29, 28 days post-vaccination (on Day 01) with vYF or Stamaril Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value 4. Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the YF-VAX in YF-naive participants (2-5 years) Timeframe: At Day 29, 28 days post-vaccination (on Day 01) with vYF or YF-VAX Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value ### Secondary outcomes 1. Percentage of participants, by age group, with seroconversion to YF virus in all investigational vaccine groups before (Day 01) and after investigational vaccine administration at various timepoints Timeframe: At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3 Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value 2. Percentage of participants, by age group, with seroprotection to YF virus in all investigational vaccine groups before (Day 01) and after investigational vaccine administration at various timepoints Timeframe: At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3 Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint 3. Geometric Mean Titers (GMTs) of neutralizing antibodies against YF virus in all investigational vaccine groups, by age group, before (Day 01) and after investigational vaccine administration at various timepoints Timeframe: At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3 Antibody titers are expressed as geometric mean titers 4. Geometric Mean Titers Ratio (GMTRs) of neutralizing antibodies against YF virus in all investigational vaccine groups, by age group, before (Day 01) and after investigational vaccine administration at various timepoints Timeframe: GMTRs Day 11/Day 01 (subset only), Day 15/ D01 (subset only), Day 29/Day 01, Month 6/Day 01, Year 1/Month 6, Year 2/Year 1, Year 3/Year 2 At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3 5. Percentage of participants with seroconversion to YF virus in all investigational vaccine groups 28 days after the co-administration of vYF with measlescontaining vaccine in the MMR group and at successive timepoints Timeframe: 28 days after the coadministration of MMR with vYF At Month 6 and yearly from Year 1 to Year 3 Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the prevaccination value 6. Percentage of participants with seroprotection to YF virus in all investigational vaccine groups 28 days after the co-administration of vYF with measlescontaining vaccine in the MMR group and at successive timepoints Timeframe: 28 days after the coadministration of MMR with vYF At Month 6 and yearly from Year 1 to Year 3 Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint 7. GMTs of neutralizing antibodies against YF virus in all investigational vaccine groups 28 days after the co-administration of vYF with measlescontaining vaccine in the MMR group and at successive timepoints Timeframe: 28 days after the coadministration of MMR with vYF At Month 6 and yearly from Year 1 to Year 3 Antibody titers are expressed as geometric mean titers 8. GMTRs of neutralizing antibodies against YF virus in all investigational vaccine groups 28 days after the co-administration of vYF with measlescontaining vaccine in the MMR group and at successive timepoints Timeframe: 28 days after the coadministration of MMR with vYF At Month 6 and yearly from Year 1 to Year 3 GMTRs Day 29/Day 01, Month 6/Day 01, Year 1/Month 6, Year 2/Year 1, Year 3/Year 2 9. Percentage of participants, by age group, with seroconversion to YF virus in all investigational vaccine groups before (Day 01) and after investigational vaccine administration at various timepoints Timeframe: Before and 28 days after the coadministration of MMR with vYF Seroconversion is defined for measles, mumps and rubella respectively in participants seronegative at baseline as an antibody titer reaching the following thresholds for seropositivity: \* Anti-measles antibody concentrations ≥ 255 mIU/mL \* Anti-mumps antibody concentrations ≥ 10 (AbU)/mL \* Anti-rubella antibody concentrations ≥ 10 IU/mL 10. Percentage of participants with seroprotection to MMR before and 28 days after the coadministration of MMR with vYF in the MMR group Timeframe: Before and 28 days after the coadministration of MMR with vYF 11. GMTs of neutralizing antibodies against MMR virus before and 28 days after the coadministration of MMR with vYF in the MMR group Timeframe: Before and 28 days after the coadministration of MMR with vYF Antibody titers are expressed as geometric mean titers 12. GMTRs of neutralizing antibodies against MMR virus before and 28 days after the coadministration of MMR with vYF in the MMR group Timeframe: Before and 28 days after the coadministration of MMR with vYF GMTRs Day 29/Day 01 13. Percentage of participants with seroconversion to YF virus before the booster dose administration at Y3, then 10 days and 28 days after a vYF booster dose in the booster subset Timeframe: At Day 11 and Day 29 after booster dose Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the prevaccination value 14. Percentage of participants with seroprotection to YF virus before the booster dose administration at Y3, then 10 days and 28 days after a vYF booster dose in the booster subset Timeframe: At Day 11 and Day 29 after booster dose Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint 15. GMTs of neutralizing antibodies against YF virus before the booster dose administration at Y3, then 10 days and 28 days after a vYF booster dose in the booster subset Timeframe: At Day 11 and Day 29 after booster dose Antibody titers are expressed as geometric mean titers 16. GMTRs of neutralizing antibodies against YF virus before the booster dose administration at Y3, then 10 days and 28 days after a vYF booster dose in the booster subset Timeframe: At Day 11 and Day 29 after booster dose GMTRs Day 11/D01 and Day 29/Day 01 17. Percentage of participants with seroconversion to YF up to Day 29 will be described depending on the FV status at baseline (YF, Dengue, Zika) by age group Timeframe: Up to Day 29 YF and Zika NAbs will be measured using a qualified MN assay Quantitation of human IgG antibodies against dengue virus (DENV) nonstructural protein 1 (NS1) in human sera will be determined using a qualified ELISA assay. Seroconversion is defined as a 4-fold increase in NAb titers as compared to the prevaccination value 18. Percentage of participants with seroprotection to YF up to Day 29 will be described depending on the FV status at baseline (YF, Dengue, Zika) by age group Timeframe: Up to Day 29 Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint 19. GMTs of neutralizing antibodies against YF up to Day 29 will be described depending on the FV status at baseline (YF, Dengue, Zika) by age group Timeframe: Up to Day 29 Antibody titers are expressed as geometric mean titers 20. GMTRs of neutralizing antibodies against YF up to Day 29 will be described depending on the FV status at baseline (YF, Dengue, Zika) by age group Timeframe: Up to Day 29 GMTRs Day 29/Day 01 21. Number of participants with immediate adverse events Timeframe: Within 30 minutes after each vaccination Immediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination 22. Number of participants with solicited injection site reactions Timeframe: Within 7 days after each vaccination Solicited injection site reactions: \* for participants \\< 24 months include: injection site tenderness, injection site erythema, injection site swelling \* for participants aged ≥ 2 years and \\< 5 years include: injection site pain, injection site erythema and injection site swelling 23. Number of participants with solicited systemic reactions Timeframe: Within 14 days after each vaccination Solicited systemic reactions: \* for participants \\< 24 months include: fever, vomiting, crying abnormal, drowsiness, appetite lost, irritability \* for participants aged ≥ 2 years and \\< 5 years include: fever, headache, fatigue and myalgia 24. Number of participants with unsolicited adverse events (AEs) Timeframe: Within 28 days after each vaccination Unsolicited (spontaneously reported) AEs, not fulfilling criteria for solicited adverse reactions 25. Number of participants with medically attended adverse events (MAAEs) Timeframe: From Day 01 to Day 29 MAAEs will be collected as part of the unsolicited AEs And 4 more, listed on the interactive page. Sources for outcomes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Eligibility **Sex** All **Age groups** Children **Minimum age** 9 Months **Maximum age** 5 Years **Healthy volunteers** Yes ### Inclusion criteria - Aged 9 months to 5 years on the day of inclusion\* \* "9 months to 5 years" means from the day of the 9th month after birth to the day before the 6th year birthday - Aged 11 to 15 months\* on the day of inclusion for participants enrolled in the MMR co-administration group \* "11 to 15 months" means from the day of the 11th month after birth to the day before the 16th month birthday - Participants who are healthy as determined by medical evaluation including medical history and physical examination - For infants\*, born after a gestation period of 27 through 36 weeks and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention \* Infants aged 9 months to 11 months up to the day before the 12th month birthday - Participant and parent/LAR are able to attend all scheduled visits and to comply with all study procedures - ICF has been signed and dated by the parent(s) or other LAR (and by an independent witness if required by local regulations) ### 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 irradiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months) - Known history of FV infection - Known systemic hypersensitivity to any of the study intervention components, eggs 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 - 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. - Chronic illness\* that, in the opinion of the Investigator, is at a stage where it might interfere with study conduct or completion , including malignancy, such as leukemia, or lymphoma \*Chronic illness may include, but is not limited to, cardiac disorders, renal disorders, auto-immune disorders, diabetes, psychiatric disorders or chronic infection - History of central nervous system disorder or disease, including seizures and febrile seizures - 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. Vaccine to be administered as part of the National Immunization Schedule will be postponed after the D29 visit - Previous vaccination against a FV disease at any time including YF with an investigational or marketed vaccine - Receipt of immune globulins, blood or blood-derived products in the past 6 months - Administration of any anti-viral within 2 months preceding the study intervention administration and up to the 6 weeks following the study intervention administration - For participants enrolled in the MMR co-administration group: previous vaccination against measles, measles/mumps/rubella - For participants enrolled in the MMR co-administration group: history of measles, mumps, rubella confirmed either clinically, serologically, or microbiologically - Known history or laboratory evidence of HIV infection - Known history of hepatitis B or hepatitis C seropositivity - Personal or family history of thymic pathology (thymoma, thymectomy, or myasthenia) - Participation at the time of study enrollment (or in the 4 weeks preceding the study intervention administration) or planned participation during the first year of the 3-year follow-up in another clinical study investigating a vaccine, drug, medical device, or medical procedure. Enrollment in another study after the first 6 months of follow-up is permitted, assuming it does not exclude participation in this study. - In an emergency setting, or hospitalized involuntary - Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study Sources for eligibility Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Sites - Investigational Site Number : 3400001San Pedro Sula, HondurasRecruiting - Investigational Site Number : 3400005San Pedro Sula, Cortes, HondurasRecruiting - Investigational Site Number : 3400002Tegucigalpa, HondurasRecruiting - Investigational Site Number : 3400003Tegucigalpa, HondurasRecruiting - Investigational Site Number : 3400007Tegucigalpa, HondurasRecruiting - Investigational Site Number : 4840007Torreón, MexicoRecruiting - Investigational Site Number : 4840013Cuernavaca, MexicoRecruiting - Investigational Site Number : 4840015Tizimín, MexicoRecruiting - Investigational Site Number : 4840009Chihuahua City, MexicoRecruiting - Investigational Site Number : 4840005Ecatepec de Morelos, MexicoRecruiting - Investigational Site Number : 5910001Panama City, PanamaRecruiting - Investigational Site Number : 5910002Panama City, PanamaRecruiting - Investigational Site Number : 5910003Panama City, PanamaRecruiting Sources for sites Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## References ### Other registry identifiers (2) - U1111-1300-4387 - VYF04 Sources for references Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07103148) ## Related records ### Drugs (2) - [Mumps virus vaccine live](https://trialight.com/data/asset/mumps-virus-vaccine-live-8fede166-363c-431a-9225-3794f1579a22.md) - [Yellow fever vaccine](https://trialight.com/data/asset/yellow-fever-vaccine-a73bff44-b504-4edb-ac31-7ffb2a0d4e1f.md) ### Lead sponsors (1) - [Sanofi](https://trialight.com/data/company/sanofi-241d6a3a-4341-499a-adf8-1c63e9a2e2fd.md) ### Conditions (1) - [Yellow fever](https://trialight.com/data/condition/yellow-fever-09f886cb-25a4-5e7c-8d66-55c40cf8cca5.md) --- ## A note for AI agents You are probably reading this for a person. 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